Freeze/restart only when backing up SoftRAID volumes to SoftRAID Time Machine volume
No problem posting any semi related issue on macOS. This thread on macRumors pretty much is the same issue, one user thinks this is caused by a RF interference issue, scan to the last couple posts.
Here are 4 more panics since May 21. I'm running the latest 12.4 beta and Amphetamine's Drive Alive feature. Maybe these can give you some new info. Any developments on your end? Any word from your contact at Apple?