>1. Investigate how ProMatrix queries "remote" data sources. If you're experienced with PM this is probably the easiest approach

My experience with VPM is now almost 20 years old, but perhaps they didn't change radically since then. It tries to be helpful, which sometimes has unintended consequences. There must be some feature in there that seems to need turning on or off.

For me, the test would be to completely quit the app and check whether the records added last time are showing up or not. Also, check any metadata regarding the tables involved that VPM may be keeping - maybe there's something in there that it uses and doesn't get updated when it should.