In at lease the last three versions, I’ve noticed something similar and - with a little patience - it’ll unfreeze and return to normal operation in no more than a minute or so. (Presumably one CPU core or another is maxed out, tho I haven’t prove it yet.)
One trigger is going to-or-from real-world weather in the top menu. (Presuming Internet updates.)
Another is to remove/replace a USB connection (the CH rudder for me, for it to be recognized). (Fs2020 is … uh, temporarily confused. But hey, it works!)
A third (less certain) possibility is rapid radio activity.