Hi rccpgm,
From your statement it's look like it's not have service impact if we suddenly connected back-to-back between vc member. But from my case it make L2 Loop due to that and make some outage. My VC member connected to one HA PABX device (Yeaster). Previous the port that connected to that PABX device threat as normal port. But suddenly that port change to VC port without config changes.
I'm already open JTAC case. EX330 with junos version 14.1X53-D35.3
Thanks and appreciate some help / guidance.