I had the same type of drop from the big ring on my previous Emonda. Ultimately it boiled down to a misaligned chainring pin (they're designed to pick up the chain and "help" it onto the big ring). The pin would grab the chain, but not release the chain when it should. So the chain would appear to have made the shift onto the big ring, but the pin would continue to hold onto the chain until the pin reached the 3 o'clock position, at which point the tension on the chain would pull the it off the big ring, completely bypass the small ring, and dump it right into the frame.

Dunno if that's what happened to you, but I'd take a magnifying glass to the inside of the big chain ring to see if you've got any misaligned pins, damaged chain ramps, or a bent tooth. It'd be pointless to get your frame repaired because this will happen again unless you find and fix the problem.