It sounds goofy but stranger things have happened to professionals. Chepkoech missed the turn to the waterjump. At the European XC a few years ago the Norwegian Grovdal (then in her late 20s with half her life running at a high level) apparently got confused how many (ca. 2 km) laps there were still to go and let Can and Schlumpf get away and later could not catch up with them; she might have won if she had not been thinking there were two more laps left.