This is a known issue that our playtime is working to fix, however, the global leaderboard does not effect any other aspect of gameplay or any of the events.
The global leaderboard is just your ranking against all other players in general, and is not an event itself, nor will it affect your position in any other events.
If you are having trouble with any other events or have any other questions, please contact our Support Team by submitting a support ticket in the game; you can do this by tapping the "gear" icon on the map screen, and then "support," or you can open an online support ticket here.