John Farley:
In my view following such airspeed anomalies it would be better for the 'system' not to disengage but to degrade to a basic attitude and thrust hold mode accompanied by a pretty serious warning about what was going on.
Sometimes, hand-flying using basic attitude instrument flying skills and a global view of all available information will usually best sort out which is invalid information. (well, perhaps not with the lack of basic skills that seem more prevalent these days.)
The accident report of the December 1, 1974, crash of a NWA 727 in New York should be required reading for all of today's active crewmembers. They forgot to turn on the pitot heaters and when "the stuff hit the fan" they got fixated on the bad information to the exclusion of attitude instrument flying.