RNF2120 - External descriptions for file not found - when EXTDESC(MYLIB/MYFILE) used

My RPGLE program uses this:
DCL-F MYFILE DISK(*EXT) USAGE(*INPUT) KEYED
EXTDESC('PRDLIB/MYFILE') EXTFILE(*EXTDESC);

(yes, PRDLIB/MYFILE does indeed exist)

I submit my compile to batch and the program is created.
PRDLIB is not in my library list forthe compile.
DSPPGMREF does indeed show PRDLIB/MYFILE getting used.

Now I have another more involved process that runs in batch, and as part of
that batch process the CRTBNDRPG command is issued with the exact same
parms I used previously, using the exact same member. In this batch process
the PRDLIB/MYFILE *FILE is actually being used and is open.
This subsequent compile produces:
RNF2120 - External descriptions for file 'PRDLIB... not found; file is
ignored.

I've also tried this format:
FMYFILE IF E K DISK EXTDESC('PRDLIB/MYFILE')
with the same results.

This actually started off as an SQLRPGLE, which produced:
SQL1001 30 17 External file definition for MYFILE not found.


Why can't the compiler find PRDLIB/MYFILE ?


thanks
-doug