Using the 3.0.3 C SDK
Sometimes playdate-scoreboards-›getScores will return as the last entry for the player score even if the player already has a score in a higher rank instead of the 10th position in the scoreboards.
It happens consistently on daily scoreboards. I'm not sure if it happens on normal ones, but it seems like it pulls the previous personal best rank and merges it with the new highest score.
