Variable definition - Rop%
I have an old file that colleagues developed and they created variables like this: Rop%. I'm trying to re-create and improve some plots, which use this variable, among other similar definitions. When I retype the variable name, Mathcad tells me the variable is invalid; undefined.
For the life of me, I can't figure out why. But it looks like the percent signs (%) have different fonts. So it looks like there's something different about them, but I can't replicate it. Please see attached.

