When I began to swim to the area where the generated chunks were pumped in, I noticed that the new ones did not appear. I stood for about a minute and swam into the void. Something strange happened: I seemed to have collapsed under the boat and looked from under the water up to its bottom. At the same time management was maintained. I tried to go back and then I was transferred to the void. Just a black screen and an interface. The character became immortal (did not respond to kill). When you try to exit the game - saving does not end, you have to turn off Java through the "task manager". When you turn on again, Minecraft writes that there was an unforeseen error. When loading the world, you are still in the same place but without a boat. I repeated it 4 times (for subsequent tests I reduced the drawing of chunks to 3x).

How to play:

1. Find a long river or sea
2. Sit in the boat and sail to the not traced chunks

With repeated launches, I discovered that the world ceases to be generated not immediately, but after some time. I attach screenshots.