Have you restored any timeshift snapshots before?
Afterwards, the grub menu can sometimes boot with configuration files from the snapshot instead of your main system.
See my post about this here:
https://forum.garudalinux.org/t/deletion-of-timeshift-snapshots-caused-havoc/4351/32
I plan on making an announcement about this later today to help inform the community, given how many people seem to have this problem.