io.netty.handler.codec.DecoderException: IntArray with size 1 is bigger than allowed 0

I was able to join my Realm server shortly after the update to 1.9.1 was released. Five minutes after joining, I tried to jump into a Minecart and was kicked (Connection Lost)

The message given is:

Internal Exception: io.netty.handler.codec.DecoderException: IntArray with size 1 is bigger than allowed 0

I quit the client and restarted. but was unable to rejoin the Realm - same error message each time.

See screenshot.