Post-major PG upgrade status and logs show OK, but no events received

Marked as bug, but depends on what outcome really is!

We have an Aurora Postgres database we recently upgraded from pg10 to pg11 major version.  We are using pgoutput with Debezium. We have done a similar upgrade before without any issue. We follow this process:

1. Shutdown app, wait for events to be consumed
2. Pause Debezium connector (pause replication slot/streaming)
3. Upgrade
4. Recreate Debezium replication slot
5. Resume Debezium connector
6. Resume app

We did initially have an error, but upon restarting the tasks later, it cleared:

Unable to obtain valid replication slot. Make sure there are no long-running transactions running in parallel as they may hinder the allocation of the replication slot when starting this connector 

Replication appears to be working (but is not) both from viewing the postgres catalog tables and the logs available on Aurora. Our debezium logs also look fine. However, no data is being published. The publications are still in place and all looks fine. I also attempted restarting the debezium postgres service but to no avail.  In pg_stat_replication, sent_lsn is advancing, but not write_lsn.

We would like to figure out the issue instead of dropping the slot and recreating, so this does not happen again.

Is it feasible that an upgrade to 1.5 of connector could possible resolve the issue (related code?)?  Any other ideas to debug?  Thank you!