Why does my signature line(s) keep disapearing?

I go to my profile, and change my sig a little (add a space or something) and click submit, and my posts show my signature. Sometime later, it goes away again. No sig, nothning, nadda.

I go back to my profile and do it again. wallah! The sig is back ... for a while. What's up with that?

Opps! Now it did.

Mine's been doing that too.....if I add or change something it'll erase other things.