The Remote Getaway advancement is not always granted when using an end gateway. This occurs both when using ender pearls and when simply moving into it.
This is not a regression of MC-270749 since there is no consistent way (from what I can tell) to get the bug to occur.

To reproduce

1. /advancement revoke @s only minecraft:end/enter_end_gateway
   

2. Throw an ender pearl through a naturally generated gateway
3. Repeat steps 1-2 until the advancement is not granted

The following demonstrates the bug with the first gateway to naturally generate on seed -1768633086023783819.

Reeeeemote Getaway.mp4