Posted Classifieds return to Draft after a few hours

Hi there I have a pretty weird problem with classifieds:

When I post an ad it shows at my site just fine, it does show for about 10-12 hours and then it returns to "draft" and I need to edit all ads again to "published".

It now happend 4 times. Very odd.

I could imagine as source of the problem that I selected no duration, in fact I am contemplating to delete this option completely (doing it manually if a member wants his add removed), after all it's my precious content :p

What you think?