I don't think it is. When you log out, you are basically requesting not to be remembered. Or else you'd be complaining about how you're remembered even after logging out
The browse to classifieds, login and logout, and remember me functions work fine for me. Maybe you need to check your local settings then come back and explain why you thought VBulletin was deleting your cookies. If this isn't a problem you're experiencing though, and you're just basing it off the 2 year old discussion, I believe that specific issue was already resolved awhile back