failed to update port status - all new OVS ports fail from this point

openflowplugin fails to update port status on creation of VM using netvirt.
it always happens on the same compute host. VMs created on other computes work fine.

this is the relevant lines in the jaraf.log
2016-10-09 07:07:17,263 | WARN | ntLoopGroup-9-15 | DeviceContextImpl | 265 - org.opendaylight.openflowplugin.impl - 0.3.0.SNAPSHOT | Error processing port status message for port 13 on device Uri [_value=openflow:79818282140722] : java.lang.IllegalStateException: Previous transaction member-1-datastore-operational-fe-0-chn-591-txn-6 is not ready yet
2016-10-09 07:07:17,364 | WARN | Thread-16795 | DeviceContextImpl | 265 - org.opendaylight.openflowplugin.impl - 0.3.0.SNAPSHOT | Error processing port status message for 0 on port 13 on device Uri [_value=openflow:79818282140722] : java.lang.IllegalStateException: Previous transaction member-1-datastore-operational-fe-0-chn-591-txn-6 is not ready yet
2016-10-09 07:07:17,475 | WARN | Thread-16795 | DeviceContextImpl | 265 - org.opendaylight.openflowplugin.impl - 0.3.0.SNAPSHOT | Error processing port status message for 1 on port 13 on device Uri [_value=openflow:79818282140722] : java.lang.IllegalStateException: Previous transaction member-1-datastore-operational-fe-0-chn-591-txn-6 is not ready yet
2016-10-09 07:07:17,576 | WARN | Thread-16795 | DeviceContextImpl | 265 - org.opendaylight.openflowplugin.impl - 0.3.0.SNAPSHOT | Error processing port status message for 2 on port 13 on device Uri [_value=openflow:79818282140722] : java.lang.IllegalStateException: Previous transaction member-1-datastore-operational-fe-0-chn-591-txn-6 is not ready yet
2016-10-09 07:07:17,576 | WARN | Thread-16795 | DeviceContextImpl | 265 - org.opendaylight.openflowplugin.impl - 0.3.0.SNAPSHOT | Failed to update port status for port 13 on device Uri [_value=openflow:79818282140722] even after 3 retries