"Device or resource busy" warnings upon QubesOS shutdown

[FAILED] Failed unmounting mount xenstore file system.

and on the bottom of the screen, reads:

watchdog: watchdog0: watchdog did not stop!
dracut Warning: Killing all remaining processes
dracut Warning: Cannot umount /oldroot

These :point_up_2: errors I get always upon power-off or restart.

Here, we got many Device or resource busy, failure messages.

These :point_up_2: I get “sometimes” upon restarting the QubesOS.

What do these errors mean? Have I screwed up something in my system?
I am using default disk-partition types (NOT btrfs, just LVM, the default ones).
The only “tweak” I did was following the TRIM guide.

Bump. Anyone have any ideas?