Bukkit

What steps will reproduce the problem?
1.join a game
2.although people are in the game, they are invisible to players (not mobs)
3.

What is the expected output? What do you see instead?
Expect to see my teammates, but I don't.  (effects teammates as well)

What version of the product are you using?
v 3.9

Do you have an error log of what happened? doesn't throw any errors

Please provide any additional information below.