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I fixed a glitch so that it should be updating the experience points as you play properly now. Also please not that the leaderboards can be cached for 5-15 minutes. Since certain things like highest level don't update that often we don't check on every scoreboard load to keep the server happy.
Case
I think what is happening is more points are being awarded to the experience as you play than are being saved, I will take a look and see if I can figure out the problem!
Case
Update. After my final game of the night it shows my level 108 but leader board only shows 107
My level at the current time is 102 but the leader board only shows 101. Of course this will change as i play it more tonight.