Once again trying to get to the bottom of why this is occurring, but there seems to be no logic to it.

Have any of you spotted any pattern (against user) as to why it's happening?

Things to look out for/consider
- having #last (which I know doesn't work) at the end of your post when you hit reply
- timings
- if it happens if you post after doing a ^this^
- any rogue characters causing it
- whether it's happening more for certain users (perhaps in certain browsers) than others
- whether it's happening more for people with www.drownedinsound.com rather than http://drownedin...
- if there's any way people are using old bookmarks to access the site but it still works
- users who use linear mode (where you can often see that a response was to a particular post)
- whether it's happening with certain thread numbers
- whether it only happens within the first few posts, otherwise the thread is fine?

If we can figure out what MIGHT be causing it, it's a helluva lot easier to fix it.

Right now we've had to take off the rebuild button as clicking it was breaking the site and not fixing threads.

I'll move this thread over to the Errors board in a day or two, but next time you see a threadsmash, especially if it happens after you post, and you can share what you did previously i.e. I this'd a post and then replied lower down. Or I was replying in a thread for the fourth time.