DecoderException - [Proxy] Lost connection to server

[DragonbornCommunity]

Error: http://pastebin.com/sC0rEZ6K
Plugins on bungeecord:
Latest RedisBungee, Latest BungeeAuthMeBridge, Latest SkinsRestorer

Bungee version #1158 downloaded from the official jenkins.

Only happens with certain players.
Deleting all player data from the fallback server (essentials, world .dat files...) did not do any difference.
Using no plugins on the fallback server did not do any difference.

When he tries to connect with 1.9 it just throws the proxy connection lost error, while on 1.8 it throws the error in the pastebin.

When he joins the server he gets instantly kicked and all the players in the server are kicked for the same exact reason.

Tested and reproduced on different computers with the same account and the same result shows up, so it is indeed a server-related problem and not client-side.

[johnfriedrich]

Even deleting the whole world on your hub server didn't do the trick? Try emoving skins restorer.

[DragonbornCommunity]

Removing SkinsRestorer did not change anything.

[md-5]

Please remove all plugins from both server and bungee. This looks almost certainly plugin induced.

[DragonbornCommunity]

Removed all plugins from bungee, nothing changed. Now trying to remove the plugins from the server.

[johnfriedrich]

Did you manage to fix it?

[DragonbornCommunity]

Updated Bungeecord and this still happens: http://pastebin.com/g7XKb2F2

[johnfriedrich]

Even after removing all spigot plugins?

[DragonbornCommunity]

Now removed all the plugins and started testing.

[johnfriedrich]

It's definitely an outdated or bad written spigot plugin.

[DragonbornCommunity]

With no plugins on the spigot server, this error comes up in the console of the spigot fallback server:

[02:27:01 INFO]: rtetin lost connection: Internal Exception: java.io.IOException: Error while read(...): Connection reset by peer

The player gets this message https://i.gyazo.com/63f01379a96e888964565bd6dbef7793.png
Error in the bungeecord console: http://pastebin.com/a8eLhWa7

Also tried to delete all the worlds, same error.
Also tried making the player join both inside/outside the RedisBungee network, same thing.

This does NOT happen to all the players, but just to a few, and when it happens all the players online in the server get kicked with the same error.