I spent an hour last night just trying to get those "vehicle challenges" done to progress towards the reward. I remember one I had like 3000/5000 of boost distance. Logged out, logged in this morning and found all my progress wasn't saved! The boost distance was 355/5000 (there were other things I had that weren't saved as well) which is what it was before I started working on it. I hope they fix this soon...