Message app duplicating messages multiple times

It started recently (13.5 update?) but Messages now seems to duplicate messages 4 to 6 times.

I have an environment where Messages is run on 2 iPads, an Intel Mac Mini, an original iPhone SE, and an M1 MBA. So mixed devices and mixed versions of OSes and Messages.

Anyone else seeing this?

I haven’t seen that specifically, but Messages does seem to have gotten significantly worse lately. Deletes don’t sync is the biggest thing, but sometimes messages received on one device don’t show up on another device for a while, or sometimes ever, and I’ve had messages I’ve deleted reappear. I haven’t tried logging out of iCloud everywhere then logging back in, that’s far more of a pain than flaky Messages, but it is very annoying, particularly when Mojave and iOS 15 and earlier worked just fine. I’ve upgraded my iMac to Monterey and my iPhone and iPad to 16.6, but I don’t know which of those caused it.