Sign with JSON + Setblock causes error only in Multiplayer mode

Sign in using JSON causes the error image below, just running mode SERVER in JSON Single-Player functions normally with Sign.

When you run is taken from the server, the only way back is by turning off command Blocks in server_ properties, after returning you can re-connect again.

You must be in SERVER MODE
https://s3.amazonaws.com/Minecraft.Download/versions/15w41b/minecraft_server.15w41b.jar

Command used in the test:
/setblock ~ ~1 ~ minecraft:wall_sign 2 replace {Text1:"

{\"text\":\"TEST\",\"color\":\"dark_blue\"}

"}

Sorry by Google translater ;D