skRayFall conflicts with scoreboards. Spigot 1.9.

/scoreboard add default
/scoreboard option default nametagVisibility never
/scoreboard team join default

---> nametags are always visible. When you remove skRayfall this problem disappears.

I don't use any of SkRayFall's scoreboard/nametag functions, it's enough to bug it out when you simply load the jar.

If you want to use scoreboards commands, please disable enableFastScoreBoards. Instructions to do so can be found here.