Premier crashes curiously - 100% activity with no activity

I am having issues with an edit.  Two 1-hour clips in a multicam timeline are causing grief. Both are 4K 100Mbps, one MP4, the other MXF.

The MP4 keeps throwing audio errors and freezes playback. If I wait a little it comes back and keeps working.

Just now the whole thing froze up and I looked at Task manager to see what was going on. The drive array showed 100% activity, but zero bytes reading or writing.  I've never seen that before.  After about 3 minutes playback started working.

Error log leading up to the issue:

This is in 24.3.0 Beta build  25.