rebalance failed with "dcp_replicator,spawn_and_wait,1" error while loading through transactions with durability as MAJORITY

Steps: 

On node 6.5.0-3821, durability as MAJORITY

1. create a transaction and load 3000 doc 
2. Add a node in and start the rebalance 
3. while rebalance is going on, update already loaded 1500 doc.
4. All the load completes successfully and the rebalance fails.

test case: 

/opt/gradle/*/bin/gradle --refresh-dependencies testrunner -P jython="/opt/jython2.7.0/bin/jython" -P args="-i b/try.ini -t rebalance_new.rebalance_in.RebalanceInTests.test_rebalance_in_with_ops,nodes_init=2,nodes_in=1,replicas=1,standard_buckets=2,sasl_buckets=2,standard_bucket_priority=low:high,sasl_bucket_priority=low:high,doc_ops=update,value_size=1024,transaction_commit=True,GROUP=IN;P0,num_items=3000,atomicity=True,transaction_timeout=3000,bucket_size=100,skip_cleanup=True -m rest"