Very weird looping problem [with video]

Hello guys !

I just installed Premiere Pro CC v9. Everything is working neatly, except for this problem : Weird Premiere bug - YouTube

I basically just click to play the sequence, and it starts looping. But it's not a normal loop as you can see, and I have checked several times that the "Loop" option is disabled.

I've tried searching in the options and turning hardware acceleration (CUDA) on and off without success. Note that all preferences were by default when this bug appeared.

Any help please ?