Regular townies turning into spellcasters?

I'm also having a blast playing here. I have Islander premades showing up and becoming spellcasters... I'm in my Stardew save and those sim haven't been to Sulani or really know any residents yet so I guess the game pulled them in. I'm not worried about it... if I don't want them to be spellcasters later I'll just replace them.... I haven't played with them yet anyway.
There's always more than one way to skin a .. hmm.. to do things.