all em(4) bridge members endlessly link cycle after one loses and regains link
Put em NICs in a bridge, unplug and replug one of them, and all the em bridge member interfaces go into continual link cycling.
I have a test setup in place on a 7541 that replicates. Haven't had time to get into it beyond confirming it happens.
Somewhat similar symptoms to old bug #846, but not the same.
also discussed here. https://forum.pfsense.org/index.php?topic=106554.msg593095