Struggling to get GREP to work with ligatures

Hello all, I'm going absolutely bonkers over this one.

I am designing my own trading card game and I require the use of symbols, similar to Magic the Gathering. I have already created a font with ligatures and symbols to do this, but I needed the symbols to be color coded when ran through InDesign's data merge. I worked around this by assigning GREP styles to each ligature callout with the correct color, and the symbols changed accordingly. It was working perfectly.

The frustrating thing that's happening now is that I had it all working properly and even have sample cards correctly printed with the colored symbols - however, after taking a few months break from designing, I come back to the document after an adobe update and suddenly everything is out of whack. All my symbols are black only, and nothing I do can change the colors.

Does anyone know what happened, or how to fix this? Perhaps there's a way to create a font where the symbols are pre-colored so when they're called it's automatically the right color? I am really lost here, because I did a lot of research a few years back to get it working properly and suddenly all my progress has been destroyed.

Any help at all would be so greatly appreciated.