It shouldn't - I'm pretty sure that "Mark forum read" will update your read stats with the current time WHEN you click on the link. Perhaps you need to refresh your cache next time you visit the forum?
Next time you're in a forum, check the clock on the upper right - if it's not your current time (assuming you've properly set your time zone), refresh the page and see if things look a bit different.
If you keep having problems, send me a private message or email.
Someone posted in the RIP thread that it would be nice if maybe the porn line could be replaced with an RIP message like on the old slash site. I just figured it was less likely to get lost if posted here than in the middle of the huge thread on Curt.