[MC-257007] Players are sometimes considered OnGround while completely midair after a teleport

I was trying to use the OnGround check to see if all players have reached the ground, some conditions teleport them back up into the air (before they come close the ground). I noticed that sometimes I get stray triggers and I found that OnGround sometimes is 1 after a teleport while the player was never near ground.

In fact teleporting relatively (which I did for testing) does not cancel velocity so it shouldn't be related to velocity I think.

I reproduced this in a superflat with one repeating command block (at -60):

execute as @a[dx=20,dz=20,y=-55,dy=1000,nbt={OnGround:1b}] run say ground

Then I just keep spamming teleport commands in chat (with 50 blocks you gotta spam fast or you just hit the ground due to terminal velocity), with the selector above you gotta stand in x+ and z+ from the command block

/tp ~ ~50 ~

And then (somewhat rarely) this happens:

[13:54:16] [CHAT] Teleported 2called_chaos to 10.815072, -10.000000, 22.672274
[13:54:17] [CHAT] Teleported 2called_chaos to 10.815072, 35.155522, 22.672274
[13:54:17] [CHAT] Teleported 2called_chaos to 10.815072, 72.683930, 22.672274
[13:54:18] [CHAT] Teleported 2called_chaos to 10.815072, 107.878898, 22.672274
...
[13:54:29] [CHAT] Teleported 2called_chaos to 10.815072, 89.161479, 22.672274
[13:54:29] [CHAT] Teleported 2called_chaos to 10.815072, 92.370716, 22.672274
[13:54:30] [CHAT] Teleported 2called_chaos to 10.815072, 91.620543, 22.672274
[13:54:30] [CHAT] Teleported 2called_chaos to 10.815072, 98.639744, 22.672274
[13:54:32] [CHAT] Teleported 2called_chaos to 10.815072, 54.774634, 22.672274
[13:54:32] [CHAT] [2called_chaos] ground
[13:54:33] [CHAT] Teleported 2called_chaos to 10.815072, 38.234721, 22.672274
[13:54:33] [CHAT] Teleported 2called_chaos to 10.815072, 41.247289, 22.672274
[13:54:34] [CHAT] Teleported 2called_chaos to 10.815072, 44.248530, 22.672274
[13:54:34] [CHAT] Teleported 2called_chaos to 10.815072, 47.240883, 22.672274
...
[13:54:41] [CHAT] Teleported 2called_chaos to 10.815072, 164.230891, 22.672274
[13:54:42] [CHAT] Teleported 2called_chaos to 10.815072, 175.032237, 22.672274
[13:54:42] [CHAT] Teleported 2called_chaos to 10.815072, 181.913427, 22.672274
[13:54:43] [CHAT] Teleported 2called_chaos to 10.815072, 177.034594, 22.672274
[13:54:43] [CHAT] Teleported 2called_chaos to 10.815072, 183.915295, 22.672274
[13:54:43] [CHAT] [2called_chaos] ground
[13:54:44] [CHAT] Teleported 2called_chaos to 10.815072, 167.276099, 22.672274
[13:54:45] [CHAT] Teleported 2called_chaos to 10.815072, 158.476596, 22.672274
[13:54:46] [CHAT] Teleported 2called_chaos to 10.815072, 161.436887, 22.672274
[13:54:46] [CHAT] Teleported 2called_chaos to 10.815072, 160.477121, 22.672274
[13:54:46] [CHAT] [2called_chaos] ground
[13:54:48] [CHAT] Teleported 2called_chaos to 10.815072, 100.717423, 22.672274
[13:54:48] [CHAT] Teleported 2called_chaos to 10.815072, 103.677492, 22.672274
[13:54:49] [CHAT] Teleported 2called_chaos to 10.815072, 110.557534, 22.672274
[13:54:49] [CHAT] Teleported 2called_chaos to 10.815072, 117.437559, 22.672274
[13:54:51] [CHAT] Teleported 2called_chaos to 10.815072, 65.517571, 22.672274
[13:54:51] [CHAT] Teleported 2called_chaos to 10.815072, 72.397560, 22.672274
[13:54:52] [CHAT] Teleported 2called_chaos to 10.815072, 79.277544, 22.672274
[13:54:52] [CHAT] Teleported 2called_chaos to 10.815072, 86.157522, 22.672274
[13:54:53] [CHAT] Teleported 2called_chaos to 10.815072, 89.117494, 22.672274
[13:54:53] [CHAT] [2called_chaos] ground
[13:54:54] [CHAT] Teleported 2called_chaos to 10.815072, 92.077462, 22.672274
[13:54:55] [CHAT] Teleported 2called_chaos to 10.815072, 44.077387, 22.672274
[13:54:55] [CHAT] Teleported 2called_chaos to 10.815072, 50.957351, 22.672274
[13:54:56] [CHAT] Teleported 2called_chaos to 10.815072, 42.157300, 22.672274
[13:54:56] [CHAT] [2called_chaos] ground

Linked issues

duplicates 1

MC-108209 Testfor OnGround:1b after teleporting causes check to always output true Resolved

Comments 2

Brain81505 2023-03-18T05:27:15Z

Does this issue still occur in 1.19.4?

Arisa Bot 2023-10-14T04:34:59Z

Thank you for your report!
We're tracking this issue in MC-108209, so this ticket is being resolved and linked as a duplicate.

If you would like to add a vote and any extra information to the main ticket it would be appreciated.

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