Replication for Avamar with Data Domain failing

I have two Avamar systems that each have their own Data Domain. We are migrating to a single Data Domain that contains more storage than both data domains. We would like to retain all the existing data for future use (backups have to remain for a number of years). Going through documentation and best practices, it seems you should not replicate between Data Domains but rather connect the new Data Domain to the Avamar systems and perform a replication. I ended up doing the following:

- Created a new Data Domain storage point on each Avamar. I see the new mtree's created on the Data Domain with the unique identifier in the name of each avamar.

- I set this data domain as the Replication point

- I setup replication between Avamar A and Avamar B. This was successful and has now replicated all data to Avamar B on the new recovery point.

I tried to do the same replication between Avamar B and Avamar A, however, it keeps failing. I believe this should work but have been unsuccessful. Both are at 19.4 version and I confirmed NTP servers are configured correctly and time matches. Is there anything else that is needed on the Data Domain for this to work?