On my friend's realm, I have been working on an elevator, that uses Marker armor stands, and those armor stands have to have a dummy scoreboard value for this to work. And I had successfully added the score to all of them, I could do /say @e[score_shaft_min=1] and it would say their names. Basically, it worked great. However, after a while of playing, I would go to use it, and it wouldn't work. So I would do the same say command, and it couldn't find any of the entities with that value. No one had been on to change this, and I know for a fact, there is no command block modifying these entities' scores. And the armor stands were still these, so I would have to add it back, and it would work, and then later again it did the same thing. And no the entities are not being killed or replaced, same armor stands. But they keep losing scoreboard data. The objective is still on the list, it still exists, but the armor stands lose it. And both of these times they lost their score, it happened after I died either naturally, or by kill command. And if it helps, these armor stands do undergo tag changes and motion changes. But score never gets changed.