The NETCONF messages sent to a device do not have elements in the RFC-required order. For instance, with the device data model containing this part

container root {
list policy {
key name;
leaf name

}
}
}

and a POST sent to http://localhost:8080/restconf/config/opendaylight-inventory:nodes/node/mexample/yang-ext:mount/ with data

<?xml version="1.0"?>
<dhex:root xmlns:dhex="http://acme.com/ns/example/dhcpd">
<dhex:policy>
<dhex:name>e</dhex:name>
<dhex:rule>
<dhex:name>rule-default</dhex:name>
</dhex:rule>
</dhex:policy>
</dhex:root>

this RPC is sent to the device:

<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="m-19">
<edit-config>
<target>
<candidate/>
</target>
<error-option>rollback-on-error</error-option>
<config>
<root xmlns="http://tail-f.com/ns/example/dhcpd">
<policy>
<rule>
<name>rule-default</name>
</rule>
<name>e</name>
</policy>
</root>
</config>
</edit-config>
</rpc>

But this is not valid, since the element "name" must be the first child of the element "policy", as required by RFC 6020.

Note that there is already fixed yangtools YANGTOOLS-282 but it does not seem to apply here.