Sometimes, when you're just playing normally, some chunks fail to load, causing the entire chunk to be made of void_air. If you step in these "ghost chunks", you will glitch out because of a server-client disagreement about what block you're standing on. Mobs will also glitch out and spin rapidly without being able to move. This can be fixed temporarily by leaving the world and coming back, or pressing F3 + A to reload all chunks. This seems to happen more and more often as you move away from the last spot where the world was reloaded.
The potential reason for why this happens is because the server has trouble processing the new height limit changes, while the client is completely fine. The last time this happened was when singleplayer was changed to an internal server, so it is probably caused by a client-server disagreement of which chunks are trying to load.
Post-21w16a edit: this doesn't seem to be likely anymore, since it still happens eventhough the height changes were reverted.
Related issues
is duplicated by
relates to
Attachments
Comments


There isn't enough information here. Please provide more information such as seed & coords and/or reproduction steps.
Also we need info about render distance, processor, graphics card, ...

Relates to MC-214898

Chunk/section loading issues in water: https://www.youtube.com/watch?v=LhCd__Lr8Rs
Render distance 16.
Might provide more info if I can reproduce it generally.

@unknown is this a "stronger" version of what was happening since 1.15? If so, could this be attached to this report as related? To be more specific, I'm talking about MC-70850
Not really, no. It's sorta similar in that sometimes chunks don't render, but with MC-70850 it only happens when the chunk is partially obscured. This is not the case here, from what I can tell the reason for chunks not rendering is the chunk rendering system being overwhelmed.
Also MC-70850 is happening for a lot longer than just 1.15

So far, I couldn't find reproduction steps, creating another world with the same seed will not have the same missing chunks at the same location, but when I encountered another missing chunks area, I did some basic testing; the video is rather lengthy (~15 minutes), but maybe showing the issue extended may give some of you some pointers where to look, what could be the cause: https://www.youtube.com/watch?v=GiF7IdENN30
Some general observations (numbers are video timestamps which show what's mentioned):
With F3 turned on, you'll see as Biome "Waiting for chunk..." when you're in the affected missing chunks region (whole video)
Reloading all chunks (F3+a) does not do anything
The missing chunks go all the way down to Bedrock level; from underneath, you can see the actual amount of missing chunks (2:45)
The - at least from some angles - not rendered chunks make out a straight line (4:15), although the not rendered chunks are not actually affected and pop back into existence, dependent on how you move your camera; the actually affected missing chunks will make a hole all the way down, whereas the only seemingly missing chunks won't, when you look down (7:45)
If you move the player camera, neighbouring chunks outside of the "straight chunks line" may not appear as well and pop back and forth in/out of existence (4:30, 9:00)
Mobs you push, spawn, or walk into a missing chunk will freeze and shake (10:00, 11:10, 11:20, 11:40, )
The same goes for items; you can see this best with items if you activate hitboxes with F3+b (12:45)
You cannot place any blocks inside the missing chunk, also not falling blocks (0:45, 10:45);
it is possible to setblock a block, however, it will not show up visually (1:05, 10:55)If you place water at the border of the affected chunk, it will not flow inside of the missing chunk (13:15)
If you open the world to LAN and get a second account in, this second account will also see the very same missing chunks and experience everything the same
[media]The player does not fall through the missing chunks, they will stand like on invisible blocks (12:20); walking inside a missing chunk is very slow, as if on soulsand/inside cobweb
Despawning of items inside missing chunks is not affected
Changing the render distance (16 > 32 > 10) (4:00, 9:05) does not affect the missing chunks rendering, still more than the actually affected missing chunks will show up as visually missing from some angles
Relogging fixed the missing chunks for me; the water I placed before at the border of the missing chunk flowed into the previously affected chunk, the stone I setblocked before could now be visually seen
While relogging fixes this issue, this is not the case if you have a 2nd account around the area, and then relog; as long as the host/main account is in the world, this issue will persist, at least in Open to LAN worlds, for also other players (unsure about actual servers atm)

I also found this bug! I recorded it immediately and the footage shows me trying to interact with the world + animals.

Seems I've found the same bug too, snapshot on 21w10a on Windows 10 system. I needed milk to remove a Bad Omen status, and walked/ran in survival mode from my base a few hundred blocks away as seen in the location -338 79 -223 and found the chunk. Walking across the invisible blocks is extremely slow. I took a few screenshots and one image of the F3 text shows "Waiting for chunk..." message. Saving/exiting the game and reloading it resolved rendering the chunk properly.
[media]
Same error on
OS : Windows 10 Pro 64-bit
Java version : 11.0.10 64-bit
CPU : AMD Ryzen 5 5600x CPU @ 4.6 GHz
GPU : NVIDIA GeForce RTX 3070
Drivers : GeForce 461.72
RAM: 16GB

I has this happen to me once while there was a skeleton in the chunk, it kept shooting at me even though I couldn't see it or shoot back

[media]
[media]
[media]
[media]
This is another example of it happening

This happened to me back on 11a but havent experienced it so far on 13a
Can confirm in 21w14a.

21w15a both with caves and cliffs datapack, and without the datapack.

I think this is the same bug that I experienced, uploaded video of it and screenshot of my video settings in 21w15a ~PIAF7B.mp4

Can we strikethrough the last few lines of the description, being that this still is happening despite the world height being reverted? It is a good thought and is important to note that this issue arose around the time of the new world height, and may be correlated; however, isn't a direct cause of the different world height.

How 1.16.5 is affected?

@unknown Edited.
I can't reproduce this in 1.16.5, I really tried very hard. Flew everywhere around the world for hours and hours. The issue occurs (at least) much more frequently in the marked snapshots. But this may still be because I'm just not producing enough lag or my computer is performing too well.

I am able to reproduce in 21w18a. Anyone else able to as well? I made a new report because it might not be the same issue: MC-225063.

See this comment on MC-224893.