Riding llamas triggers "Flying is not enabled on this server"

Can you provide more details? What exactly were you doing before you were kicked? If possible, could you provide a short video showcasing the issue?

So here is the video: https://www.dropbox.com/s/qgv18ewdndh4fta/llama_flying.mp4?dl=0
Can't upload it directly because of 10Mb limit.
As you can see, llama was falling on the block under it right before the disconnection. This doesn't happen every time, though.

Looks like MC-98727

Only works with llamas, though.