I am clearly logged into my own account(NNYYMM). However, at the above screen shot, you see as I am logged as Qonad.
It happens when i enter the main page of forum.
Same problem as Lazybum. http://www.head-fi.org/forum/thread/516432/cannot-view-private-message
yea it seems so too!
So far, this appears to be limited to users of SingNet. We'll have to examine the cache control headers we send.