The F-16 has Stabilators. They articulate on separate pins that allow deflection in opposite direction, to enhance (to put it mildly!) Roll. They of course deflect in concert, when selected for Pitch only.
If GG had one Tab fixed in ground-only aspect, and the other operable in flight, one gets the 'same' effect, though obviously the poor mans' version. Roll is enhanced along with Pitch trim. I'm going to assume the elevators remain affixed to the single Tube/hinge barrel that carries both, aligned identically.
Interesting trick. Under severe load, one can imagine an asymmetrical span wise loading on this Tube, and the potential for vibration, even flutter, or buzz. The drag of Trim, on the left, is spent on Yaw capture when turning, and makes elegant use of Drag that would otherwise go to waste. If the pilot is flying trim, mechanically, this sytem has some issues relative to load (torsional) on the tube, and on the HS bellcrank, and cables. When back driven, the system would be subject to variable loading, unless damped in some fashion, and this set up would want some serious monitoring.
Unlikely, but possible, is the loss of Elevator continuity, if the actuating frame had a break in the attach to the tube. Since control is asssumed to have been pilot/unavailable anyway, it isn't impossible that the Elevators were flapping in the airstream, following, instead of leading the flight path.
The flight path after the snap looks eerily ballistic, it is too smooth to have controls inputting directional leads.
wrench, I missed your bit about the asym tab purpose, but does this proposition sound in any way applicable?