Sorry, I tried to edit my post to clarify that better. What I meant was something like it reappeared with some messages between from yesterday, then the week be

Sorry, I tried to edit my post to clarify that better. What I meant was something like it reappeared with some messages between from yesterday, then the week before, but not very cohesive. Like some deletes failed or something. It was like a chosen few messages survived, and waiting longer didn't seem to have any effect on them disappearing. I'm sad I had to delete the conversation, but this wasn't the first time I was sent an image or something and it.. just wouldn't be there on a device and there was no way to make it download. So it seemed something was corrupt, or misbehaving. (As an aside while trying to sort everything out over the past day or so, a message from someone else was only on my iPad afterwards (it disappeared from my Mac and iPhone), and toggling sync did not cause it to propagate anywhere..)