>, but “Membrane Associated Ring-CH-Type Finger 1" being converted to MAR-1 defeats me.
No, that's not what's happening. To clarify...
If you type a 41 characters long string of "Membrane Associated Ring-CH-Type Finger 1" into a cell -- Excel will not convert that to a date of MAR-1.
On the other hand, it's if you type an 6-char abbreviation of "MARCH1" that looks like a realistic date -- Excel converts it to MAR-1.
I can just about understand that "No" might cause a problem, but “Membrane Associated Ring-CH-Type Finger 1" being converted to MAR-1 defeats me.