Time mismatch when going from child to parent comp

Hi There,

I have a really annoying problem and I can't seem to find where it comes from:

When clicking a pre-comp in your main comp, usually the time indicator matches the time you have in your main comp. (i.e. 00:30:00 in main comp, gives you 00:30:00 when clicking on pre-comp)
Now, this is no problem. But when I click back to my main comp, my time indicator shift 10 seconds back. So when I'm at 00:20:11 and I click back to my main, the timer gives me 00:10:11.

Anyone any idea which causes this sort of timing mismatch?

Thanks a lot!