Of concern, to me at least, is what happens if two sensors fail at the same time in the same way (yes incredibly unlikely - but same sensor design/ heating, same drain holes - same cloud), the good sensor input would be rejected and flight controls act on bad-data for a short time?
Sensor Validation-Of course you are correct, it is disagree not fail.
Probably not so unlikely as you indicate considering the likely abrupt transition to the inside of a rapidly growing Cb. A perfect setup for a common mode "malfunction".