Players are removed from their scoreboard team on my Spigot server as soon as they move (this includes changing the direction in which they look).

I run this command:

    /scoreboard teams join TeamName @p

and then, without moving, this command:

    /scoreboard teams list TeamName

I get listed as though I am in the team properly:

    Showing 1 player(s) in team TeamName:
    <my username>

Then, I'll move my player, and run the same command again:

    /scoreboard teams list TeamName

I get a message saying the following:

    Team TeamName has no players

The above^ also happens if I add myself to the team, move, and then list the players in the team. It only lists me _until_ I move. It happens to _all_ teams.

I should also note that one of the plugins appears to be creating a team named `collision`, which automatically adds players to it. It re-appears even after I remove it. I have no clue as to which plugin is creating this team, and have no way to tell without deleting each plugin individually.

Server Plugins (1.12, run on Aternos):
 - OldPvP (maybe this one?)
 - BloodEffects (maybe this one?)
 - Citizens
 - InstantRespawn
 - Multiverse-Core
 - NickNames (maybe this one?)
 - WorldEdit
 - WorldGuard