scoreboard.dat filling with dead entities

In our world there are many entites given scores and killed by our datapack. The bug happens when a already dead entity gets assigned a score. The entries in scoreboard.dat are not removed and will stay there indefinetely causing the file to grow huge in a matter of hours. This results in Auto-Save times of about a minute after a day of playing and us having to delete the file itself resetting all scoreboards.

An example datapack is attached