I had previously entered a bug report for this issue and it is still not fixed for me after updating to 11.3U2 on my source and target machines.
The previous bug report is (it is marked as resolved): https://jira.ixsystems.com/browse/NAS-104781
Though the replication task shows as running, it is not updating the percentage complete.
I am using SSH+NETCAT as the transport.
I would be happy to provide any other infromation you need.