The July Update under “Pause When Warm” talks about how the unit operates now and how it will soon operate. It will pause when it is operating too warm and resume after it cools down. Currently it just powers through with the potential for a degraded cut. None of the Pre-Release units have as yet experienced a temperature related problem. That’s not to say the Production units will operate at the same temperatures as the Pre-Release units. We just don’t know.
Continuing the discussion from July 2017 Update (latest):
Pause when warm
"Another feature that’s coming soon is the ability for your Glowforge to pause when it’s over temperature. Today, when your Glowforge is operating in a room that’s too warm, it just keeps going - even though cut and engrave quality may suffer. Thermal pause extends the lifetime of your tube by letting it cool down when the room it’s operating in is too warm, and ensures that long prints in a warm environment look as good at the end of the print as they did at the start. It’s pretty neat - the print just pauses for a minute (or more if it’s hot in the room), then resumes right where it left off. The improved cooling system on the Pro works with the feature so it can operate in a warmer room and pause less, too."