Teleport flags not retaining passengers on cross-world travel

[BeatThis101]

Expected behavior

I use teleport flag to retain passengers and passengers are kept when you teleport from 1 world to another. (it works fine for teleporting in the same world)

Observed/Actual behavior

It literally does nothing. Teleport effects called with the retain passengers teleport flag, if the player has passengers and they are being teleported to a new world, do absolutely nothing. I get no errors, no chat messages, the player just doesn't get teleported.

Steps/models to reproduce

1. Create a new papermc server (I tested it on 1.21.4 and 1.21.8)
2. Make a new paper plugin and somewhere in there (probably a command/event) teleport the player to a location in the nether (or any alternate world) using teleport flag retain passengers
3. Run the plugin & add a passenger to the player, then run the command/event to teleport the player.
4. Watch as nothing happens

Plugin and Datapack List

Paper version

1.21.8-R0.1-SNAPSHOT

Other

No response

[Doc94]

Already reported here #12737

[BeatThis101]

This issue seems a bit different because it works for me to do what they did in their example, of teleporting to the same world you are already in. This issue only occurs when you travel across worlds for me.