Dayum, Spring. I'm not seeing this, nobody else seems to be seeing this either. Just you.
I know you use Linux and who knows what else. Have you tried using a different computer, a windows machine, a Mac machine, different operating systems besides Linux, different browsers . . . . etc. etc. etc.
Borrow a friends machine and internet (in other words go visit someone out of town) preferably a user that has a different internet provider than yours. See if you still get black squares. I'm betting that you won't unless said friends set-up is EXACTLY like yours.
!! FOXTROT JULIET BRAVO !!