I've always thought Airbus speed indications to be very sensitive.(almost like the hole in the front of the pitot is too large) so the sudden onset of turbulence would give very rapid reading changes. Interestingly we got into some rough stuff (a320)at 37000 over the alps the other night. Air speeds were fluctuating rapidly+15 to -25 kts, with the speed trend arrows going off the scale. Whilst the auto (guidance) pilot stayed engaged and auto thrust did not chase the speed.
But whilst the turbulence was quite sharp edged I would say only moderate but the speed indications would have had you believe the aircraft was out of control. Obviously it was not but the speed indications looked horrendous / stupid. In my mind this would have added the confusion to the crew after the uas event.
(note I have more hrs on Boeings product than AB ( quite experienced on both )), & find the Boeings airspeed indications more damped than the AB)
Whilst 16 pitch at height would look totally un-real I suspect this crew were totally confused by ALL the indications & warnings. Imagine the Capt coming back in and seeing hearing all that, would he as well be confused thinking 16 up going down noise warnings coming & going that can't be right "what has happened to the flight instruments they are reading crazy they must be at fault."
Humans are not good at multiple shock analysis coupled with fear & sceptasizm.