Isn't a major feature of consensus algorithms for them to be tolerant to failures? Even basic algorithms take error handling into account and shouldn't be taken out by a bit flip in any one component.

Yes. To clarify, my understanding of _this_ particular incident was wrong because it was based on reading the report of a previous incident.

But for the 2008 incident I read and linked the report, that was what happened. The ADIRU unit did probably get a SEU event and that should have been mitigated by the design of the ELAC unit. The ELAC unit failed to mitigate it so that's the part that they probaby fixed.