[MC-86082] Cannot summon an entity with a custom UUID

Hi,

I wanted to summon an entity with a custom UUID to combine with the "ownerName" in some projectiles.

But it seems that it's not possible anymore:

    /scoreboard objectives add test dummy
    /scoreboard objectives setdisplay sidebar test
    /summon ArmorStand 275 56 920 {UUID:"8ed0f252-5fea-41e6-9189-75915fb00b9c"}
    /scoreboard players set @e[type=ArmorStand] test 1

And each time I have a different UUID displayed but never the one I specified.

This UUID is one that the ArmorStand once took
There's only me and this ArmorStand in this world (no other entities) and my UUID is not that one
Even with "2-2-2-2-2" as UUID the problem is the same. It worked back in some previous snapshot (in summon and in ownerName) but not anymore.

Thanks

Korko