As a workaround, I'm going to create a dummy image (duplicate of
the PDF in question; just renamed) that I'll load at app startup.
Perhaps there is some PDF functionality that isn't always being
initialized?
With the workaround, I can no longer reproduced this issue. Also, I
cannot reproduce it with the original compiled app now! Something
external to the apps must exist such that it somehow got corrupted.
At any rate, the workaround is harmless and should this ever crop up
again, the dummy image I load should 'eat' the strange issue.