This seems conflicting with what I read about its behavior. It should heavily throttle (underclock) itself, but shouldn't destroy itself. Maybe you got a defective unit or the hot thermal environments caused issues elsewhere (again maybe due to some defect).
I had a power supply with similar problems which actually started on fire - I had been restarting it repeatedly after it kept (supposably) hitting thermal or some other shutdown condition.
Lesson: just because there are protections for going past limits doesn't mean that everything is fine when you are constantly hitting them. (applicable to our current government problems sadly)
Oh, I'm sending it back to be looked at. The hat that comes with the picade doesn't have space for a heatsink or fan under it (as the instructions are put together to assemble it) so I'm also suspecting that its early doors for the Pi4 and picade still.
