End Gateway does not always spawn player on a safe platform (may end up in the void)

Verification builds:
1.11.0.4 Beta | Windows 10: Yes

Summary:
When using an End Gateway, the player is not always placed on a safe platform, and may end up falling some distance instead. In the attached test world, the player can fall into the void and die.

Steps to Reproduce:

1. Launch the attached test world End Gateway Void.mcworld
2. Use an Ender Pearl to travel through the End Gateway

Observed Results:
The player is teleported, but does not spawn on the cobblestone platform. Instead, the player falls into the void below.

Expected Results:
As there is a safe platform available, the player should be teleported there.

Screenshots/Videos attached: Yes
gateway_void.mp4

Notes: