File opens in RPG III

I have spent a lot of time trying to modify this vendor program. It is
used to set flags and submit an end-of-day job. We never modify the
parameters it presents on screens. So, purpose is to just have this thing
get fired off by the job scheduler for an unattended end-of-day. It does a
lot of questionable stuff, and I am not convinced I have found all the
weirdness buried in this thing.

A CL calls it. I have specifically added libraries to the library list.
If it is a test run, I add test libraries in front of anything else. I
also change the current library for either production or test.

Testing it today, using the test libraries, and I verified the library
list is correct, the RPG program updated a file in the production
environment, despite that same file existing higher in the library list
(lower number).

I thought that the library list was used when RPG opens files. The
original CL has no OVRDBF commands to change anything. Yet, here I have a
production file getting changed.

I have to ask a really stupid question: Am I correct that the library list
is used to locate files when RPG opens them? There is no ILE in this
thing.

Thanks for any assistance.

John McKee