Control confusion

That Seattle Times article on the problems with Boeing's certification of the 737 Max reads as a classic of investigative reporting.

If I am understanding it correctly, however, what remains unclear s why the MCAS system was triggered at all during both flights, shortly after takeoff.  (The report says it is only meant to be activated "in extreme circumstances far outside the normal flight envelope".)   Was the single sensor it relied on faulty on both planes? 

The whole rush to get the plane certified, and the FAA's delegation of a large part of that task back to Boeing, all paints self regulation in a poor light, yet again.