I currently run Mint, Zorin Lite, and Debian. Mint owns the GRUB. The latest Zorin update took over control of GRUB. I rebooted into Mint and did a boot repair to give control back to Mint.
Now, boot into Zorin, and 5-10 seconds after login, Zorin reboots back to GRUB menu. How do I fix this ?
There are several things that can cause a Login Loop.
Since you reinstalled Grub on Mint, you may need to update initramfs on Zorin OS.
If this was me... I would start with:
sudo apt install --reinstall zorin-os-lite-desktop
to ensure that the Display manager is configured properly and all packages are proper.