Okay, thank you for the Picture. Yes, You used it for the Shell. That Font Color is not a new Problem here and it seems to be some Kind of Bug. When You use for the Sehll other Themes than the Zorin One's, you have this Effect. I had the same Problem:
A really Solution unfortunately isn't here. At least I didn't found one. I've found something that you could call a Workaround but it is more like a ... Mixture of Coincidence and Luck. I tried to manipulate the .css but had no Luck with it.