I have implemented the rules-based solution on multiple dimmer/switch groups in my house.
The intent is that an action taken on one member in a group is reflected on all others.
Initially, I deployed this solution on a SmartThings V2 hub.
Things worked but, ocassionally, I would experience the problems described here
That is, an on/off or dimmer action would cause the switches in the group to forever bounce back and forth between the old and new states.
The lights would forever go on and off, on and off … or they would forever brighten and dim, brighten and dim …
Because of its native Matter over Thread capability and the relatively recent hub replacement support, I “upgraded” to a SmartThings/Aeotec V3 hub.
Things got much worse.
Rather than the problem occasionally happening, it consistently happens.
Consistency is better for finding and correcting the problem, I suppose, but I have yet to do that.
This appears to be some kind of race condition.
My understanding is that the V2 hub is actually a faster machine than the V3 version so that factor might weigh into who and when races are won.
The worst case seems to be when a switch action is quickly followed by another.
This is a typical human interaction for my dimmers that have dim up and down buttons.
So, I gave up on synchronizing the dimmer state.
Still a stutter on the on/off switch can start things looping again.
Ugh!