The leaderboards were not filtering out players that joined but quit and therefore had 0 games or a 0 time (for parkour).
The biggest problem was a parkour course leaderboard where the top spots were taken by players with their 0 time because they never completed the course.
Leaderboards now filter out the invalid entries.

Also did a minor reformat of some messages in messages.yml. You won't see these unless you rename or erase your messages.yml and generate a new one to amend or use.