After issuing a mid-air teleport command (done by sign command links) I was repeatedly kicked off my own server. It says a crap-long message

Connection Lost
Internal Exception: io.netty.handler.codec.DecoderException: com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1

and just stops me from joining. It then displays 'back to server list'. (Thanks to the reporter of bug MC-82968, I had the same message but column 1, not column 2, and I couldn't be ****ed to write my message from scratch (I checked, and the report was the same, except for column 1) and copied and pasted to save time.)

Steps to reproduce:
1. Place a sign.
2. Use a blockdata command to change text 1, 2, 3 or 4 (I had it on 4) to /tp @p x y z (MUST be out of render distance from sign, preferably over 10,000 blocks and y must be mid-air)
3. Right-click the sign and observe.

From what my friend (who was on my server at the time) said, I also believe that the server froze and/or crashed. (I closed it by doing file -> close, so I am not sure if it would have auto-closed)

From what I know, this does not occur with respawning or /tp [name].

Thx,
--Trads