There is a serious breach of Airbus in the certification standards. The CS 25 document requires, paragraph 1309 (c), that pilots be informed of any failure so they can take appropriate action. If the pilots had been warned that 2 sensors were blocked, they never tried to test the proper operation of protection systems in which these probes are the main element.
CS 25.1309
(c) Information concerning unsafe system operating conditions must be provided to the crew to enable them to take appropriate corrective action. A warning indication must be provided if immediate corrective action is required. Systems and controls, including indications and annunciations must be designed to minimise crew errors, which could create additional hazards