Debian 12 system randomly hangs after suspend or hibernation

It's a laptop from 2010 that has been running XP, Debian 9, Windows 10 and now this new Debian 12 system, and only in this last one it shows this problem: sometimes it resumes ok from suspend or hibernation, but sometimes it hangs a few seconds after resuming. It's weird because it's not totally stalled for a while: caps lock LED turns on and off, I can Alt-Tab and the white border of the next window shows but not the contents. I can do CTRL+ALT+F2 and the text console shows, I type the username but I never get the Password: prompt. After that it totally hangs and even the caps lock LED does not change. Ctrl+Alt+Del doesn't work either. Interestingly, it still answers to ping from other PC in the LAN, but a ssh connection can't be established Sometimes (very rarely) it has happened without suspending but after sitting there idle for some minutes, it is running ok while it was sitting idle (I can see that because the tray clock shows the correct time) but after some clicks or commands it hangs and the clock stops updating I tried: * disconnecting all external devices like USB mouse and USB sticks * using the suspend/hibernate commands in XFCE menu as well as pm-suspend, systemctl suspend, and echo -n mem > /sys/power/state * checking different log files in /var/log: they don't show anything related to the crash (the timestamps go from the last seconds of running correctly, to the new boot) The only thing I can think of is that for the first time I'm using an encrypted swap partition (both / and swap were configured with LUKS with the Debian installer). Could this be the problem?