Your submission could not be processed because a security token was invalid.
 

Hi there,
I have been having this problem - when I try to mark the forums as read - since I have updated from 3.8.4 to 3.8.5
Quote:
Your submission could not be processed because a security token was invalid.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.

Any idea?
Thanks in advance.