So I use both thunderbolt ports on my Macbook Pro Retina for monitors.. on Friday of last week it was working fine, MacSierra 10.12 Sometime on Saturday I installed the 10.12.1 Public Beta 1, everything seemed ok until I came into my office and plugged both monitors into the 2 Tbolt ports. My Left monitor never turned on. I unplugged and re-plugged a dozen times, nothing. If I unplug the active right monitor that is working, the left monitor turns on. This doesn't appear to be a hardware issue at that point. I boot into diagnostic mode and both monitors work. It generates a VFD002 error which I send to Apple. Apple issues out 10.12.1 Public Beta 2 which I HOPE fixes the issue, nope. So my left monitor no longer displays when plugged in. If I unplug the right monitor the left one turns on. If I plug the right monitor back in it never turns back on. If I unplug both monitors, I can plug either one into either of the 2 tbolt ports and the ports work perfectly fine.. it's just they don't work when 2 are plugged in. I've tried resetting NVRAM and SMC, nada. EDIT: TL;DR - Both ports dont work simultaneously. I can plug my right monitor individually into either port and it works. I can plug my left monitor into either port and it works. If I plug both in, only 1 works. Anyone else have this odd issue?