As requested, I turned on the tracer and then exited OOTP22.
Then I deleted all the files in the fg_files folder. All 1,746 files so that's 1,745 fg's and the readme.txt. Then I double-clicked OOTP22 to load the game. It spun up and I could see the installation banner at the top. You can watch it here:
https://www.youtube.com/watch?v=NE7xGn1Q-3A
Again, this banner and reinstallation/rewrite of the folder contents only happens if I remove all the fg's (or certain fg files or the readme or something else to trigger it to think a reinstall is necessary - still can't determine the tripwire). But after that tripwire is tripped, it seems to insist that these particular 1,700+ fgs must be the only version for these players I'm allowed to use.
Here are the tracer files from the OOTP22 load where it is reinstalling those fgs. I didn't open the particular game file as the issue happens before then (on opening the game itself, not a particular sim)
Thanks!