This is set in mkinictpcio.conf … by default … for some reason … even when a font is not configured. Seems an odd choice to me … but it wont hurt anything. I removed mine.
This can be fixed by installing upd72020x-fw … though it is not needed.
Another choice - modern manjaro ISOs use grub-btrfs even if you dont choose it during installation.
You can opt to remove it and use regular grub.
This is a message grub always throws on nvmes.