I am working with BBB Bullseye XFCE image 2023-05-03
I have been able to image an 8Gig SD and boot from SD multiple times over the past 2 weeks.
However, each time I flash to eMMC, (by following the /boot/uEnv.txt instructions) and remove SD after flashing has booted down, the BBB when restarted goes to the login screen, accepts user ID and password, then turns to a black screen showing mouse pointer (which I can move) then returns to Login screen.
This only happens from eMMC. When I deactivated flashing in the /boot/uEnv.txt on the SD card and reboot from SD, it works perfectly.