XDC Num Documents replicated consistently drops during rebalance at destination cluster with ongoing load/mutations.

Setup a 2:4 uniXDCR.
Load 3M items on source, replicate 3M on destination.
Start some load/mutations on the source
Failover and add-back node on the destination.

Observing some strange stats behaviour on the "Outgoing Replications" Tab on the source.

• Docs replicated drops from 3M to 2M and is consistently dropping.
  This should not be the behaviour, we are not re-replicating any documents.
  Adding the graph by the hour on this.

The correct behaviour for this should be a continuously growing graph, where new mutations are accounted for.
This incorrectly represents the replication behaviour.

Also, the secs_commit drop during rebalance on the destination cluster. Which should again not be the case?