MCH6801 - Object domain violation with "duplicated" command

This is *not* a critical item, more of a "would be nice to" and even a
curiosity thing.  My immediate fix is to have the command just call a CL
that issues the WRKMBRPDM command.

At v5r2 in another shop (I think they were at security level 40, but could
have been 30), I retrieved the source for WRKMBRPDM into a different named
member (WMPU), changed the file parameter to default to my development
source file, compiled and life was good.

In a new shop now, at v5r3 and security level 40, I try to do the same
thing; the command compiles, but running and even prompting the command
generates MCH6801, violation type 1 (Object domain violation).

Both the original WRKMBRPDM and my new WMPU command objects have "Object
domain: *SYSTEM", "Allow change by program" is YES for my command and NO for
the IBM command.  The IBM command object is "Digitally signed" with
"System-trusted source", whereas mine is not.

(My immediate fix is to have the command just call a CL that issues the
WRKMBRPDM command.  So, I have a workaround.  I'd just like to know what's
going on, and why it's behaving diffferently than before.  I also tried
duplicating the WRKMBRPDM object to my named command, tried CHGCMDDFT
CMD(WMPU) NEWDFT('FILE(DANDEVLIB/DANDEV)'), but this doesn't work because
"No default value exists for specified qualifier.")

TIA,
Dan