What I expected to happen was...:

I was on a Mushroom Island (our starter base and worldspawn point) and got into a boat to drive to a nearby jungle.

What actually happened was...:
At last I saw a ship ruin - I was not really far away of my shore.
After a short time I got kicked. Error message was something abnut "server connection.."

I have checked the Server and it was was shut down (restarting), because of game crash (see crash report attached).

Seed: -273854083221815966

Steps to Reproduce:

I can reproduce this. Everytime we or one of us tries to swim with a boat to the jungle biom from mushroom biom (see picture attached)

1. starting at around coordinates x +1260 z -2176
2. jump at shore into a boat
3. drive toward jungle biom (see picture) (coordinates: x+2483 z-2091)

4. connection lost / server crash after short time driving in boat - I could see my shore. Was not far away. Unfortunately I could not write down coordinates. Server crashes now after I relog again.

And I cannot relog, I am not in my boat at relog. When I swimm just a second, the server crashes again. (see second crash report )

When I relog and jump into the boat, the server crashes too.
No chance to play.

Other info: same error and java exception error I got yesterday with snapshot 18w20a (see crash report 15.05.2018).

We made it to this jungle. and the server crashes on our way back to base (mushroom biom - see screenshot).

We had to do a backup. And when we do not leave our chunk all works fine....

Attached seed picture and the actually crash report from 16.05.2018