When you summon e.g an ArmorStand and give it a score, the score disappears after unloading the chunks. This is incredibly annoying for map makers, who need to use move-able locations.

For example claims (that I invented) and multiple (mini)games or adventure maps who need to track entities for a longer time. Also most servers might use ArmorStands to create floating text.

I came across an older bug report that had a solution: clear all UUIDs when mobs die, because I still think that tracking all mobs that ever existed is stupid as well...

I hope that this will be fixed asap as I am waiting to release my vanilla server (with claims)