Players are unable to connect using Minecraft 1.7 client. Travertine (BungeeCord fork that allows 1.7) shows this error:

On the Spigot side it just shows this:
Blabla lost connection: Internal Exception: java.io.IOException: Error while write(...): Broken pipe

I am using Spigot 1.8. Is this a Travertine or a ViaRewind problem?

I can confirm that 1.7 players are getting crashed due to failing to be removed from a Team.