what chunk high cannot loading

Put the summary of the bug you're having here

I went to the swamp adventure, but after I rowed there, some blocks (height) could not be loaded (16 grids).

What I hope to happen is...

Completely load the chunks and take risks in the marshes

What actually happened is...

The Chunks cannot be loaded, sometimes it is close to a little stealth after loading, sometimes high latency occurs.

Steps to Reproduce:

1. go far away (no more than 490 squares).
   2.looking at the chunks, the height does not appear, and a "collision box" appears.
   3. the chunks has been loaded outside, but the height of the chunks is not yet ready.
   4. stealth chunks, after the delay is finished!

Sometimes, this vulnerability will collapse if you try.Sometimes FPS is low, and 60% of the people (most) appear.