I think the problem may be that the order of the posts is decided by time they were submitted, but not an an accurate enough level, mabey it should also sort the posts by seconds to get rid of this bug (assuming that thats how they are sorted).
I remember (at least I think I do :) awhile back Dani said something about the two servers that host the site had different times, so when they time stamped the posts there were discrepancies, only noticeable if they were very close together. She fixed it then, maybe the problem has come up again. Or perhaps it could be something else entirely.
That post was from September last year, almost a year back. Plus Dani promised something like that won't happen again. Maybe this needs to be brought to her notice since this might be the same problem or something new.
Subscription Spy is displaying the times incorrectly (as in not chronologically). Notice the times in red are the same thread and the same time while the ones in blue are the same thread, same time. I was thinking it might relate to the posting quickly problem, which is also noticeable in this thread (Bob_180_Bob's posts near the bottom)
This problem just now happened to me in this thread. My last post and the one after it are in reverse order. Lardmeister post #4 was there before I made my post. And when I hit the Post Quick Reply button I got an error of some sort (don't know what it was).