I can say that this happened a few times to me.
I'll be going through the depression forum, reading the highlghted threads with new replies but not actually replying to any yet. I'll click a thread ( let's name this Thread A) and then continue and read a few more. I'll then try click the next thread, from the depression forum homepage, Thread B. Instead of loading that Thread B, it will display Thread A. I'll try going back and reclicking Thread B.
I have tried both clicking 'back' on my browser ( Mozilla Firefox) and clicking the link on the word 'Depression' at the top of the page to get back to the Depression homepage. I have also tried clicking on other threads, both highlighted and \non highlighted and they load fine. I try Thread B and it still loads Thread A. The only way I can load Thread B that I have found is to wait an hour or so, re login and then it will load fine. I don't know if it is the time passing or the relogging in that fixes it.
I wish I could tell you which threads they were, but this last happened to me about a week ago so I don't remember. I think it may have been a thread by Scorch I was trying to access and a thread by Stressless kept appearing instead. However the other time this happened before, it has been different threads and different users.
Next time this happens I will try logging out immediately and logging back in to see if that is what fixes it. I will also see if clearing my cache helps. I'll also post on here if it happens to me again, but it happens at random for me so I don't when that will be.