We're noticing that when posting into a thread, the new posts appear to post out of sequence, but after the poster backs out and takes a fresh look at the thread, the posts are all in correct order. This has happened multiple times to multiple users.

Please check this using a default installation with all themes, plugins, and applications disabled. Also ensure any caching server side is disabled. If you are then still having the same issue, please provide instructions on how to replicate the problem, and I can take a look.