It's SUPER old, going back all the way to when I first implemented this upgraded text system (I used to have a different system that was much worse):
Colored text where really shouldn't be.

It mostly happens with this specific message, though I've seen it on others during the battle as well. Altough, now that I'm trying to test it, I've seen it show up in the first message ("it's a beautiful day outside") a lot. Sadly I'm trying to replicate it by essentially spamming Z and X and resetting so I quickly lose it before I can react.

Most of the time, it consists of the color being, instead of black, a random shade of green, but this time it was blue. Yeah, sometimes it's blue. Actually, it used to always be green, but now about half the time it's blue. And when I've seen it on other messages I only recall it being blue.

It's hard to replicate. By which I mean I have no idea how to make it appear. Likewise I currently have no clue why it happens or how it could happen when the text string explicitly says it should draw itself black.

So, I don't know how to fix it.

Ok. I'm lying. I have a hunch about what might cause half of this problem to happen. It's not the half that lets me actually replicate it, but if I'm right... then I don't like it.