But the "dynamic stall" phenomenon does not really apply to light
airplanes. It is is an unsteady stall phenomenon which can be
experienced by the retreating blade of a helicopter in forward flight
and by highly maneuverable fighter aircraft.

Rich, it's true the phenomenon is most important in helicopter flight,
but it certainly happens in airplanes as well.

I have a copy of a NACA flight test which shows a 30% increase in lift
with a rapid AOA increase, in airplanes. The increase in lift was
directly proportional to the rate of AOA increase and showed no signs
of leveling off; the test pilots just got scared, and quit. :-)

What I'm curious about is under what conditions it happens. The only
difference in a snap roll and what these pilots were doing is your
application of ruddder (as far as I can tell). Perhaps the fact that
you stall one wing earlier than the other short circuits this effect.
I'm curious.