if I change system time while running http://upload.wikimedia.org/wikipedia/commons/4/4f/Soccer_ball_animated.svg then the animation stops for a while but when i reach the previous time it starts to play again.
I can confirm the bug on qtwebkit (qt 4.6, linux32-bit).
Confirmed in gtk+ linux amd64 release.
Funny bug, I have reproduced it in Debian/testing (32) and Windows Vista (64) using trunk version of the WebKit.
*** This bug has been marked as a duplicate of bug 31256 ***