Help! I have a cell that has no formula - formatted as text. But as soon as
I type a word into a second text formatted cell that first one autofills with
a formula that makes it equal to the second one.

i.e. if I type "test" into cell A12, then cell R12 automatically writes the
formula =$A12

And it's only on certain cells, not the whole sheet. I have no formula in
either cell. It's like conditional formatting only with formulas.

I've tried copying a non-wonky cell & pasting it over the afflicted one.
This works while the sheet is open, but as soon as I close & reopen it, it's
back. What would cause this to happen? the cells in reference are
DataValidation cells, but otherwise I have no code or macros associated with
this sheet.