TFL got more memory Saturday, and rebuilding the indexes got fowled up Sunday night. I didn't notice until mid-morning, but I suspect the broken search index was making the new-post process unreliable. After a post gets committed, it gets indexed for searching. That second part was failing, and vbulletin isn't the most robust web application on the planet. So a problem that should have only affected searching (which is irrelevant because the search index is being rebuilt at the moment, and it'll get to those new posts in a day or so) ended up causing inconsistency across the board.
“The egg hatched...” “...the egg hatched... and a hundred baby spiders came out...” (blade runner)
“Who are you?” “A friend. I'm here to prevent you from making a mistake.” “You have no idea what I'm doing here, friend.” “In specific terms, no, but I swore an oath to protect the world...” (continuum)
“It's a goal you won't understand until later. Your job is to make sure he doesn't achieve the goal.” (bsg)