Glitchy chunk rendering since 1.15 pre-release 2

Can confirm. The interesting part is that chunks that are already loaded/rendered suddenly unload (as can be seen around 00:09) for no apparent reason.

This behavior again is new in 1.15-pre2.

Creating a new amplified world, and waiting a bit before flying towards the edges of the world will reproduce this. 

However, when i first reproed I did so on a client that had been running overnight. My impression is that this issue was much more noticable then. 

I can still reproduce it in 1.15 pre3, shown in this video https://www.youtube.com/watch?v=itf6gPlFTmc

While it eventually fixes itself after a while of waiting, I have to be in the same place for a while for it to do so.

I can confirm it's not fixed in 1.15 pre-3. Reproduced using a new amplified world in creative mode and spectator mode.

Same for me: not fixed in 1.13 pre-3

Still happens in 1.15 Pre-Release 6. Render distance changes don't affect this bug.

Confirmed for 1.15. See

.

Yes, bad perfomance Chunks, reload map ver 1.14.4 a 1.15

It happens even without amplified world, and does so constantly.
https://youtu.be/xq-hc-mPZTU

It usualy breaks more where rendering was paused.
https://youtu.be/f22wPwsxGm4

Uploaded 2 new schreenshots with 1.15.2.

It happens far more often if flying fast using spectator mode.

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Can confirm for the 5 minutes I was on the snapshot lol

Can report that this is happening in the new 20w22a snapshot too.

Happens frequently in 1.15.2 when flying around with elytra and rockets. You can make it happen quicker by maxing out the view distance. 

I can reproduce this myself on 1.16.1, please let me know if any help or more info is needed. I have attached my DxDiag, also a screenshot of my game while the issue is occurring - it's not just that it is sometimes slow, but all of the sudden already loaded chunks close to the player disappear again for a moment. The easiest way to reproduce for me is to fly around in an elytra.

Similar to Alex, I am experiencing the same issue. (I can reproduce the same glitch in a vanilla server). I had my friend tested on his PC but unable to produce the glitch so I am suspecting it might be related to hardware. Attached are both DxDiag of me and my friend. 

and 

Me and my friends are getting this issue like crazy on a multiplayer server. It happens most when we are flying fast with an elytra and fireworks in the overworld. (1.16.1)

Yeah, me too. Thought it was just lag, but I guess it’s a glitch

Can i have ownership as the user has not been active since april?

Yeah i get that as well but it's only with my world, not with other worlds.

I had this problem a few weeks ago and it mostly went away by itself before coming back with a vengeance this weekend. I've also noticed that when this glitch happens, it can take ages ( >3 minutes) for the game to save in single player.

I had a bit of a further play about with this bug. I started up a brand new world in creative mode and blasted around it with a pair of elytra, and with the exception of a couple of times the rockets lagged a bit (and it was a bit slow but not dramatically slow loading going through nether portals), I didn't have any problems with chunk loading. Total time to save once I exited was 25 seconds. I then went into a very old world with heavily developed chunks, and the problems cropped up within seconds. I teleported to an unexplored part of the world to generate brand new chunks, and the problems still cropped up. Total time to save once I exited was over 2 minutes. Hope this is helpful in some way.

Can confirm in between versions 1.8-1.16 in a survival singleplayer and multiplayer world.

Then it's probably not this exact bug. Early 1.14 versions for example had a different kind of chunk rendering issue and 1.13 had different issues again, but 1.12 for example almost definitely was not affected by this specific bug here.

Probably relates to MC-214898

Can this be reproduced in 21w18a?

Yes it can be reproduced in 21w18a if u are on a world with extended height, that is, a world with the caves and cliffs preview datapack. I have tested.

I think I'm suffering from this in vanilla 1.17.1. Is that possible?

This bug is still present in 1.17.1 and 1.18.

Also present in all 1.18 experimental snapshots and 21w37a

Can confirm in 21w39a. Very rarely, chunks will just outright refuse to load for up to 20 seconds.

@slicedlime Still not fixed in 21w41a

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This still occurs sometimes in 21w41a. Can confirm not fixed.

Can confirm as well that still happens on 21w41a.

We've decided it's best to create a new ticket for this issue instead of reopening it. If you can reproduce this in 21w41a then feel free to create a new ticket.

I created a new ticket: MC-239031. If someone already created a new issue first, please resolve it as a duplicate.