The answer from the user is...
Shoot, I'm not absolutely sure, but I don't think that did show up. It wus weird. But the same "weird" both times it happened. Just BANG, back to the thread, no intervening activity. And that new thread view WAS fresh. Because the 2nd time it happened somebody else was posting at the same time. His new post showed even though mine didn't.
So far, no problems this week. If nobody else reports it, we may be chasing a ghost.
I am continuing to remind all users to please report if they experience this behavior. So far nothing but lots of posts from members saying that all is well with QR.