Editing the fovTop and fovLeft in the *.Arma3Profile file changes the size of fonts in the game. This only applies to certain fonts (there are some pictures of examples, not an exhaustive list), and this bug seems to be "new" as in this video: https://www.youtube.com/watch?time_continue=1&v=aiocdCeAn0Q from July 2016 this person changes his FoV, but the font is a normal size as the server message at the end of the video is a normal size.
Here are a few screenshots with the small text:
Here is a screenshot with normal text for comparison: