The 11 oldest entries on the AirTable are from 2020-12-04, which gives the false impression that these are the oldest discrepancies on GOG, whereas that date is, I assume, simply the date you started collecting this information.
If you want, I have the real dates for the discrepancies of six of these, which you could update manually:
2020-12-04 1118073204 Sphinx and the Cursed Mummy => 2020-01-20
2020-12-04 1196128708 1971 Project Helios => 2020-08-11
2020-12-04 1333227204 Double Kick Heroes => 2020-08-13
2020-12-04 1920288044 Mutropolis Demo => 2020-09-11
2020-12-04 2086192498 Indivisible => 2020-06-23
2020-12-04 2147483119 Leisure Suit Larry - Wet Dreams Dry Twice => 2020-10-23
The remaining five are more problematic, so I don't want to commit to dates for them.
Specifically for the two Project Zomboid, it is my understanding, while I don't own the game, that there is a beta offline installer, which you are not testing for, which is being updated independently of the "abandoned" default offline installer, and which is currently up-to-date with galaxy. So I think you can delete these from the list, probably indefinitely, unless you plan to test for beta offline installers (which other games might also have).