All text displayed in GNU Icecat appears overly pixelated at times

While using GNU Icecat, at seemingly random positions of the page, when scrolling down, all text on the screen becomes overly pixelated to a point that makes it rather hard to read. I haven't heard of anyone else having this problem, so I figure that it might be due to some settings I have enabled/disabled? I apologize if this has already been brought up somewhere else but I wasn't able to find any other threads on this.

I haven't encountered this problem in Firefox, Tor or Seamonkey either. This is solely an issue with GNU Icecat.

I'm using Slackware Linux, if that's of any consolation.