[Chi]

Same thing happens to me, no worries.
I think it has something to do with not posting or being in the forums? -Shrugs.-
But I understand what you're saying.
When changing my avatar I get a message that says, "You must be logged in to edit your avatar." and all the sudden I'm logged out.
A temporary fix for this is if you don't want to get logged out, click the "Remember Me" check box and you won't get logged out unless you choose to.