I believe that the bug is related to Wayland. It can be fixed by not using it as described here: https://askubuntu.com/questions/1349544/alttab-stops-working-after-a-while-in-ubuntu-21-04/1359821#1359821
I believe that the bug is related to Wayland. It can be fixed by not using it as described here: https:/ /askubuntu. com/questions/ 1349544/ alttab- stops-working- after-a- while-in- ubuntu- 21-04/1359821# 1359821