I really don't think so. It was supposed to be a breakaway stage, and as a punchy guy who had lost time yesterday, he looked like a likely contender. Both to the oddsmaker, as well as to some punters.It is sometimes just an outlier but silly odds like Onley's today can suggest insider knowledge, you'll get more of the nationalistic stuff in bigger races as not many casual betters paying much attention to the Dauphine on a working day.
I doubt anyone betted on him because he thought DSM would work for him all day to then beat Alaphililippe in a sprint.