UUIDs on scoreboard get cut off after reloading the world

When reloading the world, UUIDs on the scoreboard get cut off on reloading the world, making them useless.

How to reproduce:
summon ArmorStand x y z {UUID:1-2-3-4-5}
scoreboard objectives add test dummy
scoreboard players set 1-2-3-4-5 test 200
scoreboard objective setdisplay sidebar test
==RELOAD WORLD
testfor @e[score_test_min=200]

You can see the entity 1-2-3-4-5 is no longer linked with the scoreboard. The scoreboard now looks for a player with name:
00000001-0002-00
Which can never be an entity.