Every time I boot Xbox, I check for App Updates, and Xbox OS updates, check the network, then launch MSFS.
But even before I got that far, I noticed the MSFS icon had a progress bar on it, indicating it was automaticly updating. It could have been the new “Add on” for WASM. Regardless, there were certainly other in-app content updates for Premium, Deluxe, and each World Update. So, a lot of new code between end of beta test and final release.
I believe the code would come from a variety of sources, highlighting the problem and need to test it all together before final release.