Boeing's efforts to recover from the 737 Max scandal just aren't flying. The company admitted Monday that a previously-undisclosed software problem stopped certain safety alerts from flashing up as expected. The Wall Street Journal reports the alerts could have warned pilots that the plane's stall-prevention system—suspected to have been involved in the Lion Air and Ethiopian Airlines crashes—was about to misfire. Those two crashes killed 346 people and grounded the 737 MAX fleet across the globe, sending the plane-maker into its worst ever crisis. The alerts could have warned pilots about a possible disagreement between two separate sensors which measure the angle of a plane’s nose. The new admission suggests both Boeing and U.S. air-safety regulators either missed or overlooked the software problem when the model was deemed safe to fly in 2017.