I've multiple jails connected on different bridges with associated VLANs - all come back to a single lagg (2 physical interfaces).
Before upgrade to 11.3-U3.1 they worked perfectly, but after upgrade, the iocage jails come up but networking is not working. Cannot ping default gateway. iocage jails on the same bridge can ping each other ok
Boot to old boot environment resolves the issue (old = 11.3-U2.1)