I'm using "minecraft.tools" to give myself a custom sign to give myself a boat and when I enter this into a command block and give it to myself and place it down I crash. When I try to join the server I crash still, its when the sign is loaded. I will put the command below and attach the error message. Creating a singleplayer world and opening it to LAN doesn't create this bug. It also occurs if you try replacing an existing sign with /blockdata ~ ~1 ~.

Command: /give @p minecraft:sign 1 0 {BlockEntityTag:{Text1:"{\"text\":\"Pick Your\",\"clickEvent\":

{\"action\":\"run_command\",\"value\":\"give @p spruce_boat\"}

,\"bold\":true,\"underlined\":true,\"color\":\"green\"}",Text2:"

{\"text\":\"Boat\",\"bold\":true,\"underlined\":true,\"color\":\"green\"}

",Text3:"",Text4:"

{\"text\":\"Spruce Boat\"}

"},display:{Name:"Custom Sign"}}