If the redundance is at system level, and the three sensors are identical, redundancy is absent.
Thales had corrosion problems at the drain, I do not recall if they rose to the level of AD. Regardless, the probes performed sufficient to satisfy the certifications protocol, and that is acceptable. After the fact does not obtain to this crash.
Redundancy had thorough airing in BA038, where BOTH engines failed, within seconds of eachother. The Heat exchangers were found to be of insufficient design. Instead of changing engine manufacturers, the Heat Exchangers were modded. An AirSpeed sensing SYSTEM that relies on three identical probes is a single system. IF there are mitigating procedures that can provide AS in a transient system failure, well and good. However, focussing on the probes only is missing the point at large, eg: system FAIL.