Can you try turning off promisc(uous) mode on the bridge and see if you still A) get working floating IP traffic from/to/between VMs, and B) don't get dupes anymore?
ip link set dev brXXX promisc off <- (for whatever your bridge device is)
Can you try turning off promisc(uous) mode on the bridge and see if you still A) get working floating IP traffic from/to/between VMs, and B) don't get dupes anymore?
ip link set dev brXXX promisc off <- (for whatever your bridge device is)