use interface wildcard "+" in iptables to cover potential used VLAN interface to allow output on physical interface.
you will see
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-out bond2+ --physdev-is-bridged
instead of
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-out bond2.1234 --physdev-is-bridged
Anthony