The probem is in Dyna-Step 3.1 which should swap to the Alternate UserID.
There is a parameter that must be added to the startup configuration for Dyna-Step's DYSSERV server:
COMPAT=ENDEVOR, <<== Add
This is an assembler macro, the options can be dynamically assembled at startup if the server is configured for that.
This fix is not documented in the Dyna-Step manual and there is no mention of it in the samples in the product target libraries. This was not found on the Dyna-Step support site either.