If you've noticed the server going up and down a bit in the past few hours, that was me scouring the database and Apache logs.
I selected all posts between the post of Peggy's that you mentioned, and your post where you said that posts were missing. This returned 661 posts. All the IDs were sequential apart from three missing, so I searched the Apache log for records of those post IDs and found that none of them belonged to thread 11868.
As there are no soft-deleted posts in that thread, and the only missing posts from the database (indicating hard-deletion) during the time period in question do not belong to that thread, I'm not sure what I can say, but there is simply no evidence of the post you describe ever being submitted. Sorry.
So that's the last hour productively used. Now I'm getting back to work.