Vehicle with Passengers or Mounted Mobs Fail to Travel Through Nether Portals

Description:
Entities riding vehicles (e.g., a creeper in a minecart/boat) or mobs mounted on other mobs (e.g., baby zombie on a chicken, spider jockey) cannot pass through Nether portals as they do in Java Edition. This behavior blocks players from transporting villagers or other mobs efficiently via portals.

How to Reproduce:

1. Place a minecart or boat inside an unlit Nether portal frame.

2. Add a passenger (e.g., a creeper) to the vehicle.

3. Light the portal.

4. Observe the entity’s interaction (or lack thereof) with the portal.

Observed Result:

• The vehicle/mounted mob and its passenger remain in the Overworld despite contacting the portal.

• No teleportation occurs for composite entities (e.g., spider jockeys, chicken-riding zombies).

Expected Result:
All composite entities (vehicle + passenger or mob + rider) should immediately teleport through the portal upon contact, consistent with Java Edition behavior.

Additional Notes:
This bug significantly impacts gameplay mechanics, especially for mob transport systems. Urgent confirmation and fixes are requested.