Nothing particularly suspicious. He transferred to a vehicle at that point, and while the GPX file directly downloadable from Strava 'joins the dots' to include that transfer, he did switch off the timer on his GPS, so the course file records what looks like the correct distance. The difference between the two is 292.75km (.crs file) and 325.25km (GPX). The summary distance on Strava matches the lower, course file.
His time-distance chart for the day looks reasonable: