From @unknown:
(The test world shared by ItsRichHeart breaks after the fix to lava-water interaction in 1.20.40, so I made a new one.)
Steps to reproduce
Load
Flip the lever on the contraption.
Move to near the side of the lower row of blocks and wait a few seconds.
Expected result
Nothing happens. You just watch the block feedtape cycle.
Observed result
You get teleported to X = 0.
After the latest update v.1.20.30
My moss farm wich is in the style of the youtuber silentwisper, now teleports me about 60 blocks downward when i turn it on.
Linked issues
is duplicated by 9
relates to 3
Attachments
Comments 12


https://youtu.be/hVImUoB0lOo
Here is a link to a youtube video of me having this issue.
Steps to Reproduce:
Have a moss farm, containing a stone generator and bonemealing a moss block.
Turn it on.
Be teleported about 60 blocks downward
Observed Results:
Auto teleported downward when near operating moss farm.
Expected Results:
Nothing should happen when i turn on moss farm.
Notes:
Im on v.1.20.30 bedrock edition on a ps5.

I have seen two other reports of this issue in Discord chats, both related to cobblestone farms. Moss and cobblestone farms have a lot of pistons firing at at once, so I would guess there is an interaction happening between the player and pistons several blocks away. In all 3 cases so far it is only one coordinate that changes, and that coordinates is set to 0. The coordinate change likely matches the direction the pistons are pushing. In the video linked by the reporter here the pistons are pushing down and the player is teleported to 0 Y. Note that the displayed coordinate is -2 Y because this is a an unadjusted server-side position update, so it is the players eye position that gets set to 0.
Here’s an example where the player is teleported to 0 X. https://cdn.discordapp.com/attachments/600409597009854464/1154151680804393021/cachedVideo.mov

Rainbowtraib: does this only happen on a realm? The other reports I’ve seen both were from realms.

Here is a video of me having the same issue: https://youtu.be/bgRygJ9sLI0?si=kXgyuKNBODDWbJ81
I am playing on a Windows 10 realm in v1.20.30. The farm I am using in the video is by centi. Video/world download: https://youtu.be/_7sburjuwtg?si=KOd6CMBXkURQc9zV

Steps to Reproduce
Open
Flick the lever of either "South" or "East"
Stand there for a couple of seconds (5-10 seconds) and turn the contraption off
Flick the lever of either "North" or "West
Stand there for a couple of seconds as well (5-10 seconds)
See the result (and use the commands to teleport back)
Observed Results:
When doing step 2 and 3, nothing happens
When doing step 4 and 5, you get teleported
For the "North" side, you get teleported to z=0
For the "South" side, you get teleported to x=0
Expected Results:
When doing step 4 and 5, you should not get teleported, just like in step 2 and 3
Notes:
For help on replicating the bug, see the attached video for a visual guide
The bug even happens if the command blocks are not there (simply pushing the block already creates the observed results). They are only there so it can keep on placing blocks
When standing above the pistons (y-level of the player is above the y-level of the piston), the player does not get teleported. Only when the y-level of the player is at the same level or below it
After further testing, at negative x and z coordinates (e.g. -1000, -1000) instead of teleporting back to x = 0 or z = 0, the game simply rubberbands and teleports you constantly back, see this imgur link for a video: https://imgur.com/a/hWaEtZX

This can be triggered by a block conveyor as well, which shows that the lava, water, and block conversion in the test world are unrelated:
[media]
Based on careful scrutiny of all of the repro videos, I think the bug triggers in the tick when a retracting piston attempts to remove its extended arm and, if it is a sticky piston, any attached movingBlock. If another block is being set in the same tick into the same place where the piston arm or movingBlock is being removed, then there is then a chance that the player gets teleported.
The payer being teleported also seems to correlate with the creation of a glitched movingBlock. You can see this by turning off the command blocks that break the cobblestone in the test world. When the blocks are not being broken, then each time you get teleported, one of the lines of cobblestone stops advancing. After all 6 lines of cobblestone stop advancing you no longer get teleported. At that point some of the "cobblestone" continues running the movingBlock animation when the pistons extend and retract:
[media]
I would explain the glitched moving blocks and player teleport this way: when the bug triggers on the retracting piston, it mini-crashes the piston's block update function, cancelling the rest of the updates that that piston was scheduled to make in that tick (so some of the blocks in a row of moving blocks do not get converted back to normal blocks) and overflowing junk data into the player's position. That's just a hypothesis of course! It does suggest a possible relation to MCPE-65970 though. Perhaps some work was attempted on that issue, which caused this one?

Still present in latest previews.

Just had this same issue with a trident killer for a mob farm. Happened regularly within 5-7 seconds of starting my 3x3 trident killer. It does use carpet to avoid the dead space, so the piston block updating makes sense. IOS Minecraft Bedrock v. 1.20.51.

still present in 1.20.51 (windows 10 edition)
Please attach a video of the issue and update the description to include steps to reproduce. The following format is recommended:
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