Versions

• Minecraft Version : 1.16.5
• Forge Version : 36.1.24
• Mod Version : 7.6.2
• Optifine Version : HD_U_G7

Describe the bug
Player riding on a horse often stay in place after using waystone, and still spend xp. Sometimes stuck on the waystone even if the space is big enough.

just experienced this bug in 1.18 (forge 39.0.5) as well.

I'm on the 1.18 fabric version and have the same problem when inside a boat. If in creative mode, using tp ~ ~ ~ will teleport to the correct location and everything works again. (Yes, interestingly, ~ ~ ~ is the target location.)

I have a similar issue in 1.18.2 with Fabric, which might be related.
First teleport went well, but the teleport dismounted me and my horse was sort of stuck halfway up the waystone. I couldn't mount it or attach a lead. I then mined a block below it (right next to the waystone), but couldn't pick that up, as if the tick rate was overloaded. Some seconds later I could pick up the block and ride the horse.
Then I did the next teleport, but noticed that my horse did not follow me, despite being mounted up (I assume having it on a lead with leave horse & lead behind). Tried teleporting back, re-mount & teleport again, but same issue persists.

Edit: Forgot to add. When I teleport back to where my horse should be, I end up being mounted on top of it.
Edit: Another observation, which is slightly game breaking… When I teleport to the other location & lose my horse, then save & quit and log back in I end up at the waystone I came from (without the exp). As a solution I figured out that you can in fact teleport with a horse on a lead, which also increases the experience cost, which seems to work without issues (and upon relog).

This seems to happen to any entities that teleport alongside you, but only sometimes. Reproduced the same and similar issues on horses and leads.

Is this still happening in recent versions of Minecraft?

I have tested on 1.21 fabric version with horse and boat and I can not reproduce the bug. One question: after teleporting, the player is dismounted from the entity. Is this an expected behavior?

Tested on 1.16.5, 1.18.2, 1.19.2 and 1.20.1 forge version and 1.21.1 neoforge version with several times (much more in 1.16.5) , teleport and xp cost behavior just works fine but having a new bug on 1.19.2+:

When teleported to the waystone in the spawn chunk*, riding horse and leashed animals 'disappeared' on the client side - could only hear them but not see or interact with them. F3 + A has no effect, must re-join the world or come back from a faraway place (reload the chunk from the server).
In 1.19.2 and 1.20.1, you can even see the loooooong lead like this:

*: Also encounter it when teleporting away from the spawn chunk by warp plate.

Edit:

I have tested on 1.21 fabric version with horse and boat and I can not reproduce the bug. One question: after teleporting, the player is dismounted from the entity. Is this an expected behavior?

Dismounting behavior happens in 1.18.2+.

To add to this, sometimes when it happens the player cannot open inventory, or even dismount and it requires a complete world save/reopen. The entire game seems to be frozen (no fish swimming, no villagers wandering, no time passes) until world is closed.

It used to work flawlessly, no dismounting either. Then one time it never did, and now consistently it does not.

Also on 7.6.2,
Forge 36.1.32
optifine U_G8