netconf connector replace causes transaction chain failure

tested with https://nexus.opendaylight.org/content/groups/public/org/opendaylight/integration/distribution-karaf/0.3.0-Lithium/distribution-karaf-0.3.0-Lithium.zip

i made some post, put and delete requests (see attachment), in random order and quantity and after while i got exception: java.lang.IllegalStateException: Transaction chain has failed

i was tested it against testtool started with command:
java -Dorg.apache.sshd.registerBouncyCastle=false -Xmx1G -XX:MaxPermSize=256M -jar /tmp/netconf-testtool/netconf-testtool-0.3.0-SNAPSHOT-executable.jar ssh true --generate-configs-batch-size 1000 --exi false --generate-config-connection-timeout 10000000 --generate-config-address 127.0.0.1 --device-count 2 --starting-port 17830 --debug false

karaf log with trace logs is also attached