to DenisG & mm43:
So you are both making the assumption that everything was fine/working with probes and:
..ISIS (22FN-10FC) SPEED OR MACH FUNCTION (2 h 11)
..FLAG ON CAPT PFD FPV and FLAG ON F/O PFD FPV (2 h 11)
were triggered by real pressure indications?
What if pressure (=speed, altitude, etc.) was wrongly calculated by frozen probes?
Condition for system faults doesn't mean that real flight conditions were actually matching those cases. In fact, it wasn't the case for all aircraft displaying similar faults in similar flight conditions (probe freezing). Just notice that most systems feeded by probes were displaying errors at the same time.