SNDUSRMSG at V5R3?

[Scott Klement <midrange-l@xxxxxxxxxxxxxxxx>]

Hello,

11 days ago I upgraded my system from V5R2 to V5R3.  Since that time, I've 
had sporadic (not reproducable!) problems with the SNDUSRMSG used in CL 
programs.

It crashes with the following error:

       1900 - SNDUSRMSG MSG('POST OF AP CHECKS ALL FILES UPDATED. ENTER G=RUN
       OR  C=CANCEL') VALUES(C G) MSGRPY(&REPLY)
     POST OF AP CHECKS ALL FILES UPDATED. ENTER G=RUN  OR  C=CANCEL
   ? *N
     POST OF AP CHECKS ALL FILES UPDATED. ENTER G=RUN  OR  C=CANCEL
   ? *N
     Tried to refer to all or part of an object that no longer exists.
     Function check. MCH3402 unmonitored by QMHDSEXT at statement *N,
       instruction X'0149'.
     Error occurred in SNDUSRMSG command.
     CPF2559 received by APUCHKCL at 1900. (C D I R)

The problem is, it's sporadic. It doesn't do this every time, and it never 
did it on V5R2 or earlier. It's not a particular program, either. It's 
happened 3 different times, all on different programs on the system.  The 
only thing these programs have in common is that it happens on the 
SNDUSRMSG command.

Has anyone encountered this?  Does anyone know of a PTF, workaround, or 
some other way to fix it?

---
Scott Klement  http://www.scottklement.com