When trying to configure OpenConfig BGP neighbor, below error is received even if the leaf mentioned in the error message is present. Problem is seen in Beryllium SR3 but not SR2, and may have started happening after merge of BUG-5830 changes. Corresponding model is https://github.com/opendaylight/bgpcep/blob/stable/beryllium/bgp/openconfig-api/src/main/yang/openconfig-bgp.yang

Steps to reproduce are as follows:
1. Deploy Beryllium SR3 controller
2. Install below features:
odl-netconf-connector-all
odl-netconf-topology
odl-bgpcep-bgp-all
odl-restconf-noauth
odl-mdsal-apidocs

3. Perform GET on http://localhost:8181/restconf/config/openconfig-bgp:bgp/global/config as ensure that mandatory AS leaf is present
4. Try to configure neighbor by doing POST of below payload to http://localhost:8181/restconf/config/openconfig-bgp:bgp/openconfig-bgp:neighbors
<neighbor xmlns="http://openconfig.net/yang/bgp">
<neighbor-address>10.10.10.10</neighbor-address>
<afi-safis>
<afi-safi>
<afi-safi-name xmlns:x="http://openconfig.net/yang/bgp-types">x:IPV4-UNICAST</afi-safi-name>
</afi-safi>
<afi-safi>
<afi-safi-name xmlns:x="http://openconfig.net/yang/bgp-types">x:IPV6-UNICAST</afi-safi-name>
</afi-safi>
<afi-safi>
<afi-safi-name xmlns:x="http://openconfig.net/yang/bgp-types">x:IPV4-LABELLED-UNICAST</afi-safi-name>
</afi-safi>
<afi-safi>
<afi-safi-name xmlns:x="urn:opendaylight:params:xml:ns:yang:bgp:openconfig-extensions">x:linkstate</afi-safi-name>
</afi-safi>
<afi-safi>
<afi-safi-name xmlns:x="urn:opendaylight:params:xml:ns:yang:bgp:openconfig-extensions">x:ipv4-flow</afi-safi-name>
</afi-safi>
<afi-safi>
<afi-safi-name xmlns:x="urn:opendaylight:params:xml:ns:yang:bgp:openconfig-extensions">x:ipv6-flow</afi-safi-name>
</afi-safi>
</afi-safis>
<route-reflector>
<config>
<route-reflector-client>false</route-reflector-client>
</config>
</route-reflector>
<timers>
<config>
<hold-time>180</hold-time>
</config>
</timers>
<transport>
<config>
<passive-mode>false</passive-mode>
</config>
</transport>
<config>
<peer-type>INTERNAL</peer-type>
<peer-as>64496</peer-as>
</config>
</neighbor>

5. Error message received is:

<errors xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf">
<error>
<error-type>application</error-type>
<error-tag>operation-failed</error-tag>
<error-message>Error creating data </error-message>
<error-info>TransactionCommitFailedException

at org.opendaylight.controller.md.sal.dom.broker.impl.TransactionCommitFailedExceptionMapper.newWithCause(TransactionCommitFailedExceptionMapper.java:37)
at org.opendaylight.controller.md.sal.dom.broker.impl.TransactionCommitFailedExceptionMapper.newWithCause(TransactionCommitFailedExceptionMapper.java:18)
at org.opendaylight.yangtools.util.concurrent.ExceptionMapper.apply(ExceptionMapper.java:96)
at org.opendaylight.controller.cluster.datastore.ConcurrentDOMDataBroker.handleException(ConcurrentDOMDataBroker.java:209)
at org.opendaylight.controller.cluster.datastore.ConcurrentDOMDataBroker.access$000(ConcurrentDOMDataBroker.java:44)
at org.opendaylight.controller.cluster.datastore.ConcurrentDOMDataBroker$1.onFailure(ConcurrentDOMDataBroker.java:117)
at com.google.common.util.concurrent.Futures$6.run(Futures.java:1310)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:457)
at com.google.common.util.concurrent.ExecutionList.executeListener(ExecutionList.java:156)
at com.google.common.util.concurrent.ExecutionList.execute(ExecutionList.java:145)
at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:202)
at com.google.common.util.concurrent.SettableFuture.setException(SettableFuture.java:68)
at org.opendaylight.controller.cluster.datastore.SingleCommitCohortProxy$1.onComplete(SingleCommitCohortProxy.java:60)
at akka.dispatch.OnComplete.internal(Future.scala:247)
at akka.dispatch.OnComplete.internal(Future.scala:245)
at akka.dispatch.japi$CallbackBridge.apply(Future.scala:175)
at akka.dispatch.japi$CallbackBridge.apply(Future.scala:172)
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
at akka.dispatch.BatchingExecutor$BlockableBatch$$anonfun$run$1.apply$mcV$sp(BatchingExecutor.scala:91)
at akka.dispatch.BatchingExecutor$BlockableBatch$$anonfun$run$1.apply(BatchingExecutor.scala:91)
at akka.dispatch.BatchingExecutor$BlockableBatch$$anonfun$run$1.apply(BatchingExecutor.scala:91)
at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:72)
at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:90)
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:397)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: java.lang.IllegalArgumentException: Node (http://openconfig.net/yang/bgp?revision=2015-10-09)bgp is missing mandatory descendant /(http://openconfig.net/yang/bgp?revision=2015-10-09)global/config/as
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:145)
at org.opendaylight.yangtools.yang.data.impl.schema.tree.MandatoryLeafEnforcer$Strict.enforceOnTreeNode(MandatoryLeafEnforcer.java:58)
at org.opendaylight.yangtools.yang.data.impl.schema.tree.PresenceContainerModificationStrategy.verifyStructure(PresenceContainerModificationStrategy.java:33)
at org.opendaylight.yangtools.yang.data.impl.schema.tree.OperationWithModification.merge(OperationWithModification.java:50)
at org.opendaylight.yangtools.yang.data.impl.schema.tree.InMemoryDataTreeModification.merge(InMemoryDataTreeModification.java:78)
at org.opendaylight.controller.sal.core.spi.data.SnapshotBackedWriteTransaction.merge(SnapshotBackedWriteTransaction.java:82)
at org.opendaylight.controller.cluster.datastore.modification.MergeModification.apply(MergeModification.java:42)
at org.opendaylight.controller.cluster.datastore.LocalTransactionContext.executeModification(LocalTransactionContext.java:50)
at org.opendaylight.controller.cluster.datastore.TransactionProxy$3.invoke(TransactionProxy.java:169)
at org.opendaylight.controller.cluster.datastore.TransactionContextWrapper.maybeExecuteTransactionOperation(TransactionContextWrapper.java:92)
at org.opendaylight.controller.cluster.datastore.TransactionProxy.executeModification(TransactionProxy.java:166)
at org.opendaylight.controller.cluster.datastore.TransactionProxy.merge(TransactionProxy.java:149)
at org.opendaylight.controller.cluster.databroker.AbstractDOMBrokerWriteTransaction.merge(AbstractDOMBrokerWriteTransaction.java:95)
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.ensureParentsByMerge(BrokerFacade.java:500)
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.postDataViaTransaction(BrokerFacade.java:350)
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.commitConfigurationDataPost(BrokerFacade.java:240)
at org.opendaylight.netconf.sal.restconf.impl.RestconfImpl.createConfigurationData(RestconfImpl.java:888)
at org.opendaylight.netconf.sal.restconf.impl.RestconfImpl.createConfigurationData(RestconfImpl.java:833)
at org.opendaylight.netconf.sal.restconf.impl.StatisticsRestconfServiceWrapper.createConfigurationData(StatisticsRestconfServiceWrapper.java:152)
at org.opendaylight.netconf.sal.rest.impl.RestconfCompositeWrapper.createConfigurationData(RestconfCompositeWrapper.java:89)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceObjectRule.accept(ResourceObjectRule.java:100)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1496)
at org.eclipse.jetty.servlets.CrossOriginFilter.handle(CrossOriginFilter.java:247)
at org.eclipse.jetty.servlets.CrossOriginFilter.doFilter(CrossOriginFilter.java:210)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1467)
at org.eclipse.jetty.servlets.UserAgentFilter.doFilter(UserAgentFilter.java:82)
at org.eclipse.jetty.servlets.GzipFilter.doFilter(GzipFilter.java:256)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1467)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1467)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
at org.ops4j.pax.web.service.jetty.internal.HttpServiceServletHandler.doHandle(HttpServiceServletHandler.java:69)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
at org.ops4j.pax.web.service.jetty.internal.HttpServiceContext.doHandle(HttpServiceContext.java:240)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:429)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.ops4j.pax.web.service.jetty.internal.JettyServerHandlerCollection.handle(JettyServerHandlerCollection.java:75)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:982)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1043)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:865)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:696)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:53)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:745)
</error-info>
</error>
</errors>