The company told Engadget that "engineering is actively troubleshooting" the problem, but didn't have more to share.

This might be a product of the GPS rollover flaw that has affected numerous devices. Some hardware will reset its GPS date when the associated clock hits 1,024 weeks, throwing off timing and thus location-finding abilities. GoPro hasn't updated the Karma since September 2018, several months after exiting the drone business -- there's a possibility that it simply hadn't addressed the reset issue by then. Whatever the cause, the grounded drones serve as a reminder that GPS-dependent gadgets aren't guaranteed to keep working unless there's an appropriate level of support.