Testing Beta 14 on a couple of live shows and the last 2 weekends now I have had this major crash bug after about 3 hours on OS X Sierra.
When triggering a clip (it doesn't matter what clip) the M8 locks up, normally in the case of a lock up or a crash you can still access the finder & the apple menu to close & restart the app. In this case the entire system locks up for about a minute then I get this scrambled screen & the menu bar inverts in colour (see below)
Then the menu bar becomes active again (although still inverted) and I can get the apple menu and select Force Quit however with the scrambled screen the Force Quit menu is not visible (I assume it's appearing behind the big black section of the screen), so the only way I can get my system back is to do a hard reboot.