.... does USAFA sometimes mail appointments without it being updated on the portal or being notified from the MOC?
Appointments do tend to come out in waves. Early, the appointments are a trickle along with LOAs but once all the nominations are made - you will see a large number of appointments announced between late Feb and early April.
Trying to draw any inference to when USAFA might do something because USMA did something is meaningless. The SA's don't coordinate at all on the process. Each runs their own show on their own schedule.
And though it may seem a lot of USAFA appointments may already be out, it is likely the majority are still to come in March/April.