Course Elevation Profile "Flatlined"

Using 2.80, and a long (27 mi) course loaded by copying a .GPX file to the device, I saw an issue yesterday where the elevation profile started just showing a flatline instead of the actual elevation. This happened mid-activity (it had started out correct). I'm not 100% sure, but I believe it happened after losing then regaining the course. The course remaining distance and time was still correct. Has anybody else seen this behavior?