Computer had keyboard error on startup.
Usually keyboard errors are caused by cluttered desks that have junk pressing on keys, or a dirty keyboard that has a stuck or otherwise malfunctioning key. The user said that the keyboard was replaced before and it still errors from time to time.
I swapped the Mouse’s USB port to a different port on the offchance that it would affect the detection order of the PS/2 KB and Mouse…it’s a longshot, but after a Reset the keyboard didn’t give errors on startup and worked fine. Will monitor additional issues and replace with USB keyboard if it happens again.