Antoine

Sorry, I didn't view your message, bug still in 1.15.1 stable release, 1.15.2 stable release and last snapshot (20w29a)

Yes it's a vanilla server

I updated the files to download.
I added 2 files called "piston 1.15.2" and "piston 1.16 rc1" which are maps where the problem occured.
First, i created the map in 1.15.2 and everything was OK and then i duplicate the map (copy and paste) and I used the copy of it in 1.16 rc1 and then the problem occured. Both maps are exactly the same, just different version of Minecraft.
(update: you can still dowload the "piston rc1" map and update it in 1.16 or 1.16.1, the bug still occur)

No

Hello @ @unknown , I guess your time is precious, so I'll try to make it fast.

I am a developer on a french server with many players connected (1k simultaneously).

And sometimes we have a problems, because some users use this bug, so that the client of others users lag.

If you will more element a Youtubeur have create an explanatory of the bug ( https://youtu.be/dSD4alSCP3E?t=4m20s ) (this video is recent and his turn in 1.13-pre3) And this exemple is equaly possible with Stairs or Hopper.

And I think is not Redstone, it's juste an aggravating factor for me of the problem, the main problem here is in my opinion the method of render when the chunk is updated, is not necessary to update the all chunk when a block,is place, the surrounding blocks is enough.

Wishing you a good end of the day,

Ant74