hey,
The switches doing it are two Arista 7050SX3 with a single instance VXLAN EVPN. It should be a pretty simple setup. Not aware of any knobs to modify any of this behavior or what we could be missing.
Hard to speak for Arista (we do also have EVPN-VXLAN implementation with 7050SX3 and A-A MH and don't see mentioned issue) but I wouldn't be suprised if this is Arista bug considered their EVPN story has been pretty rough in other similar areas (like A-S MH not blocking on non-DF etc).
Let us know if you find some correlation with other events that might explain this.
-- tarko
