I have the newest Photoshop 21.2 release running on Win 10 2004. When I use the Select Subject feature inside of or outside of the Select and Mask environment Photoshop will randomly stop working and freeze. After a few seconds the Adobe error reporting widget pops up.
When working outside the the Select and Mask environment the freeze happens when using the Quick Selection tool. When working inside the Select and Mask environment I've had the program freeze with the Marching Ants or Overlay display modes selected while refining the selection.
Though the problem is randomly triggered it is happening often.
I upgraded to PS 21.2.1 this morning and reset the settings on my GPU (Nvidia GeForce GTX 770/PCIe/SSE2 running the latest Nvidia driver 446.14) to their defaults. This included re-enabling Use OpenCL. I then went back to the images I edited earlier to see if PS would crash as before.
So far this version of PS is stable when using the 'Select Subject' feature inside of or outside of the 'Select and Mask' work environment.