This issue is similar to the problem addressed by APARs PM84130 & PM71673. Except in this occurrence, the MQRC being
The zSeries community releases support bulletins to let you know about critical problems in a product that runs on a zSeries server.
R_Password service validates password and returns 12/13 because of password length issue. CICS checks password length
Using CICS TS 5.3 callable service DFHWBCLI getting return code 8 (disaster), reason code 0. From the documentation