It’s a Grub bug, I believe in specific combination with the chronic bug on Linux that is Nvidia.
I believe you’ll be rid of it when you with e.g. sudo nano /etc/default/grub edit that file and uncomment (remove the # from the start of the line.
GRUB_TERMINAL=console
Ctrl+X to save and exit, then run sudo update-grub.
So as to boot into the system to be able to do that, hold down Left-Shift or tap Esc at the point that the boot transitions from firmware to disk (i.e., when Grub loads) and choose the recovery option from the Advanced Options submenu.