you can check it in SE38. enter program LMEGUICJM and click display, then search for 999402
if you get a hit, then the note is implemented.
Another suggestion would be to check if you are using the BAdI ME_PROCESS_REQ_CUST. If there is something wrong in the coding, then it could eventually be a root cause.
611175 - ME_PROCESS_REQ_CUST: Documentation
Since when did you encounter this behavior? what happened before? release change? new developments? implementing OSS notes? Does it work for other users?