I wonder if this is also related: 9.5.5 - Mailbox targetting issues
I’m not certain if this is related, but there is a potential issue with the FillDB parallelism introduced with 9.5.5.193+ which could affect DSA in some ways. The parallelism is on by default but could cause issues in some cases, particularly where the number of FillDB threads exceeds the server CPU count. I would recommend trying to turn it off to see if it helps:
I would recommend filing a PMR to contact IBM support about this issue.
This version should not be affected by the issue I mentioned above.