---> EDIT:
This bug affects ONLY the Snapshot 13w37b on a SERVER; in Singleplayer everything is working fine.

Steps to Reproduce:
You need a MC-Vanilla Server on Snapshot 13w37b.

Prerequisites:

/scoreboard teams add Redstone
/scoreboard objectives add joined_red dummy

1.) I made a CommandBlock which outputs a /tellraw Command where you can click on 2 `Buttons`, called Redstone and LapisLazuli.

/tellraw @p[1000,50,1000,1] {"text":"Bitte wähle dein Team! ", "extra": [{"text":"[Redstone] ","color":"red","clickEvent": {"action":"run_command","value":"/scoreboard players set @p joined_red 1"}, "hoverEvent":{"action":"show_text","value":"Spiele als Redstoneblock."}}, {"text":"[LapisLazuli]","color":"blue","clickEvent": {"action":"run_command","value":"/scoreboard players set @p joined_blue 1"}, "hoverEvent":{"action":"show_text","value":"Spiele als Lapislazuliblock."}}]}

2.)The onClick is the almost the same: It outputs a Command (Of course for the Lapis-Button it´s joined_blue.):

/scoreboard players set @p joined_red 1

.

3.)Then a /testfor CommandBlock saw that and activates an other CommandBlock.

4.) Its output is:

/scoreboard teams join Redstone @p[score_joined_red_min=1]

. The options for the Team Redstone I did set to (color:red, friendlyFire:false, seeFriendlyInvisibles:true).

What I expected to happen was that I get a red Name and will be moved to Team Redstone.

What actually happend was that I got the message "Points in joined_red for 1Darco1 set to 1" and than immediatly got disconnected with the Java IOException: "Received string length longer than maximum allowed (25 > 16)". In the ServerLog I have confirmed I were added to the Team Redstone and then were kicked with the Issue above.