World preview and Realms capture create an x-ray when the player is in blocks

Summary:
World preview and capture Realms create an x-ray when the player is in blocks.
It's better to use creative for reproduce, however it works the same way in survival, just use the water breathing effect to not die.

Steps to reproduce:

1. Go to creative. / /effect @s water_breathing 1000000 100 true
2. Break 3 blocks down.
3. Take the sand/gravel and place it above you.
4. Save the world/capture in Realm looking down.

Observed results:
Caves (x-ray) can be observed on the created image.

Expected results:
The image will have a placeholder texture (as when playing in the world).

Screenshots: