i have 2 router, rb750gr3 & hapac2.
2 ether on hapac2 is bridged & conected to rb750gr3.
why bridge interface on hapac2, get 2 ip addrs from rb750gr3.
2 ip with mac from ether1 & ether2 hap ac2.
arp list mac change freq sometime from ether 1 & sometime from ether2.
try mac-admin set & auto-mac =no but bridge mac arp still change.
because mac continuesly change sometime hapac2 is timeout.
So what is the question?
Draw a network diagram
and post your confg
/export hide-sensitive file=anynameyouwish
and finally some use cases, what is it that youd like users to be able to do or not do LOL