Sprite Font Has Weird Lines in Fullscreen Mode

I'm trying to use a custom sprite font for text in my game, however I'm running into an issue where weird lines show up in the text when the game is put into fullscreen mode.

When the text is being displayed at it's normal size, it looks totally fine. As soon as there's any sort of scaling, lines start showing up between and on the characters. Not sure what's going on, but if anyone has any suggestions on how to get rid of it, that would be great.

I've tried running the same sprite font in C3 with the same events and sprite font settings and it behaves in the same way.

Images to further illustrate my dilemma:

It's common for sprites to bleed when scaled if there is no buffer around the image. Make sure each character has 1 or 2 blank pixels around all four sides.