I'm having the EXACT same problem and I have PLENTY of available disk space. It's a random points, the audio just drops out for about 5-10 seconds, then picks up again in my exported MP4.
When I playback in my sequence, no issue with audio at all.
The ONLY solution so far seems to be to render out again and hope ... so far a 2nd render has worked. But after researching this problem and (I on Pr 22.0.0 (Build 169)) finding MANY other users with the exact same issue and no resolution, I'm kinda surprised Adobe haven't acknowledged or addressed this?