AWS DMS job works for engine 3.4.7 and below

We have Oracle DMS Jobs running for replicating ORACLE RDS data to a Replica that has all of its FK Constraints removed to avoid any issues. Source: AWS RDS Oracle Se2 Destination: AWS RDS Oracle Se2

Recently updated the engine for the EOL to 3.5.1. The jobs broke miserably with varying errors and no real root cause. Recreating the Instance and the Jobs for 3.4.7 resolves the issue.

We noticed a few of the following:

Database is not AWS RDS Oracle instance (oracle_endpoint_conn.c:584)

ORA-03138: malformed TTC packet from client rejected:

It would run and restart itself 5-6 times and then finally fail out. Any Ideas on how to troubleshoot more?

unfortunately the tech cleaned up the Logs... so we will likely need to recapture it, but it seems odd that a 3.4.7 job would begin to fail on the 3.5.1 engine.

The current workaround was to simply recreate the Jobs, Engine, recreate the 2nd DB from Source DDL etc and rescync on the older engine version. That engine is set to be EOL'd early in 2024.

Thanks in advance.