I was riding a 50km+ route (to get the badge and the XP). I was using the drone camera rider view which allows you to use the arrow keys to move the virtual camera around, so I could see my little avatar cruising down the road from above rather than looking at the same straight ahead POV for 2 hours. Well, 40km in and wouldn’t you know it, I unknowingly used the arrow keys to move the camera just as I was coming up on a turn… boom that’s it, I’m off the route, no badge. Drat! I only realized it when my HUD was no longer showing me as riding the route. A warning message like “hey you’ve been riding this route for 2 hours and you’re pretty close to a badge, are you sure you want to make this left turn?” would have been helpful.
Edit: as was pointed out elsewhere, the proper fix would be that the arrow keys on the keyboard NOT have two functions similtaneously (control your turns and operate the drone camera). There’s a whole keyboard full of keys that could have been used instead to operate the drone cam so this doesn’t seem like too much of a stretch to fix.)