@egroys,
An issue with OTA updates has been reported by some users on the official bug tracker, seems to be related to the MacOS
securebootmodel
setting in OpenCore, the issue has been seen more often with Monterey updates but it might be related to your issue.
More info here :-
Hello, I'm testing monterey and I noticed no ota update available from beta 5 to beta 6. I thought about an error on my end, even if I verified multiple times, then I upgraded from a full installer...
github.com
Cheers
Jay