Dang! I think I know how to fix that visual bug but I don't know why it would be switching fonts. I'll have to look into that.
Sorry if I didn't explain clearly, the font loaded and stayed fine, I would suggest you look for a new font that's less blocky as it's hard to read. I understand it's part of the style but there are plenty of 16bit fonts out there that I think would keep the same style while being easier on the eyes, but that is my own personal preference so take it with a grain of salt.