/setblock with signs missing Text tags kicks all players loading the sign

Warning: this bug is server-only.
Place a command block (Impulse, Unconditionnal, Needs Redstone).
Enter this command :

setblock ~ ~1 ~ standing_sign 0 replace {Text1:"[{\"text\":\"Hey\"}]"}

Place a redstone block next to this command block. Now everyone near this command_block is getting kicked from the server, with this error :

Internal Exeption: io.netty.handler.codec.DecoderExeption:
com.google.gson.JsonSyntaxExeption:
com.google.gson.stream.MalformedJsonExeption: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1

Here is the consol log :

TheMrZZ lost connection: TextComponent{text='Disconnected', siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}

Happens when alimented with a lever, a button (stone & wood), a repeater, a comparator, a redstone wire (any kind of alimentation works).

BIGGEST PROBLEM : If you do this in a spawn chunk, you can't come back because it seems to instant-kick every player near the CM, except if someone put a command like /tp PLAYER @p in a repeating command block.

See Marcono1234's comment for a description of why this happens