Same here; something is definitely not right.
After it wouldn't run, I also couldn't get it to run by rolling back PF3.exe to the 145 beta. So, I decided to uninstall and reinstall using the 3.16 downloader from Simmarket. Ran OK; updated to 3.21.0 after the first instance of "Check for Updates". Then clicking "Check for Updates" again, it prompts saying "New version of PF3 Available: 3.22.0". I click yes to download, it downloads, then asks if I want to install it, closes PF3, etc.
This time, it'll run, but it still says Version 3.21.0 under the Oncourse Software banner. Likewise, clicking "Check for Updates" brings up the "New version of PF3 Available: 3.22.0" prompt again. This time I said "No" to installing it, closed PF3 and then tried running the installer manually. But, same result. Seems I'm still stuck on 3.21. PF3.exe is dated 09/28/2023.
This also occurs with the PF3_Cumulative_Updates_Setup posted in the announcements. In total I've run the update at least 3 times (on this new reinstallation) but it hasn't appeared "to take".
Now I'll see if I can get the "not updated updated" version to still run after I've popped my backed-up PF3.ini and other ini's back into the mix.