Getting "EKF GPS datra stopped" in SITL

Over the past few weeks I’ve been getting a new error a lot in SITL. “EKF PS data stopped”. sometimes it starts right back up again, sometimes not. I don’t see any hiccups in the flight path or any failsafes trigger. I’m running fixed wing gazebo in Docker on Windows. Any ideas?

this is after letting the SITL run for a couple hours with the vehicle in a loiter: