I also have the same problem. It may occur several times in a row or it may only occur once. I did notice some casual correlations: if I had no applications open from the last session before reboot it was much less likely to occur but still does occur anyway occasionally; if I see the C (for Cachy) boot splash fully it is less likely to occur but still does occur anyway occasionally; if the black screen between login and desktop loading is longer than 5 seconds it is much more likely to occur with a longer duration significantly increasing the likelihood; and when I am returned automatically by this bug from the desktop session to the login screen I only have about 5 seconds to hit reboot before the system freezes completely requiring a hard reboot but if I do hit reboot in time I am less likely to have a reoccurrence of the issue as compared to after going through a hard reboot although it does happen in both scenarios - sometimes requiring a reboot/hard boot several times to auto correct itself. Once I have been successfully logged into a Wayland session for more than 5 minutes it has never occured.