That's generally not how redundant systems work. They'll usually implement some form of a Kalman filter or whatever cool kids use these days to filter out bad readings, while alerting the pilot that one of the sensors seems to be faulty.

Usually things that can kill people are triple redundant, where one goes bad, you can trust the other two readings for this reason.

I'm surprised there is a single point of failure like this in the design. But after I've read a bit about how Boeing released this product, maybe I'm not surprised.