Takata
If airspeed reached Mach 0.87 and triggered a nose up order, why the RTL settings would shwo Mach 0.82?
I agree, it is not easy to explain, thus my reservations about that scenario. But lets think a bit about the characteristics of a pitot tube that has iced up and closed the drain hole.
With no airflow through the tube (drain hole frozen), and with a blocked inlet, the heaters must be able to add to the total energy in the tube and thus begin to melt ice. At some point, the elbow area of the tube should melt and allow the tube to drain. With appropriate coincidences you might get a temporary return of actual pitot indications (plural) long enough to set the RTL unit to the correct value and still get into trouble by virtue of the nose attitude. But it is a long shot. Too much has to happen synchronously.
The best RTL fit is with something like a dynamic loss of control. There the aircraft pitches up into a high speed stall, freezing the RTL unit at the pre-existing correct value, since the high AOA triggers ADR disagree results similar to the Perpignan A-320. It appears that the aircraft will not over G in this situation based on HN39's analysis. Only question is how you get enough loft to account for the known time of flight. Of course, no one has published A330 flight characteristics for AOA in the 50-60 degree range. The wind tunnel tests may never have been run.