https://techcrunch.com/2020/03/18/spacexs-latest-starlink-launch-included-an-unforeseen-engine-issue/

While successful in its primary mission, the latest SpaceX launch wasn’t without unexpected issues: The secondary mission of recovering the Falcon 9 booster with a controlled landing failed, for the second launch in a row, and SpaceX CEO and founder Elon Musk also confirmed that one of the rocket’s engines shut down early during the ascent phase of the launch vehicle.

This didn’t affect the actual orbital deployment of the 60 Starlink satellites which were on board the Falcon 9, which went exactly as planned. That’s due in part to the redundancy built into the design of the Falcon 9 launch vehicle, which uses 9 Merlin engines working together. But Musk still said on Twitter that the failure of one of those would still mean a “thorough investigation [is] needed before next mission.”