Hello,
I've had this same issue before. So I applied the fix in here: http://www.askvg.com/fix-bold-blurry-or-hard-to-read-font-problem-in-windows-8-1/ and now it doesn't reproduce anymore! :D
Basically, you need to check the "Let me choose one scaling level for all my displays" checkbox in "Screen resolution" context menu, "Make text and other items larger or smaller"
LE: Hmm, it seems on facebook it still reproduces :(
Cheers.