We can argue on whether it's a "bug" outright (since it is technically a correct implementation of a faulty design), but Boeing's MCAS pitching the plane based on the input of a singular faulty sensor has probably caused billions in direct damages, and billions more in reputational damage.

NULL references (which Crowdstrike is an instance of) are often referred to as "the billion dollar mistake", but the actual cost of "historical" languages skimping out on optionally-nullable types is certainly in the trillions.