CA Datacom Multi User Facility (MUF) region is correctly shut down and the DBMUFPR step returns RC 0 but a SNAP dump (ID=20) is generated on the MUF joblog while the following messages can be found on the JESMSGLG:
DB01004E - PXX AREA I/O ERROR
DB01001W - PXX AREA FULL
DB00202I - MULTI-USER DISABLED
The errors are returned because the PXX dataset is shared with another MUF region (a member of the same MUFPLEX, a shadow MUF or a completely different one)
CA Datacom/DB or CA Datacom/AD 14.0 and above
Each region must have its own PXX and this dataset cannot be shared with any other Datacom MUF region.
This requirement is clearly stated on KB000025223 for Primary/Shadow configuration.