As you can see in this video and timestamp 13:15 (https://www.youtube.com/watch?v=62ZiObGVPyk&t=13m15s), Devildog was able to sprint and appeared to reload his gun. Of course, the two are mutually exclusive so his gun did not actually reload and he was left not knowing what happened. This is a bug from RO2 days, and I believe it occurs in certain situations where you press the sprint and reload buttons at the same time.