[Live Content Affected] Light blocks are treated as solid block on loading world

Partner Rank:
1. VERY Critical

Verification Builds:
1.17.30

Regression Builds:
1.17.11

Summary:
Light blocks seem to be treated as solid block on loading world

Affects currently Live Content:
Yes. More than one.

Impact:
This is causing one of my content to not be able to be started. This causes multiple pieces of content to send the player outside the gameplay area.

Repro Steps:
1. Download 100 Days in Minecraft, BUT...
2. You do not start in the underground, rather you are sent to the surface

1. Create new world
2. Go creative, fly around and enter a cave
3. Fill your location with light blocks
4. Quit world, reopen
5. You will spawn in higher location

1. Stand on surface
2. Fill rectangular area 50 blocks high with light blocks
3. Go survival mode, stand inside light blocks
3. Quit world
4. Reload world, you will be dead from fall damage

Observed Results:
Player is sent on top of light blocks instead of where the last location was.

Expected Results:
When loading a world, players position should treat light blocks as air. Players should not be sent elsewhere, but left in position last saved. This also affects /setworldspawn

Video:
https://www.youtube.com/watch?v=8Hw6DlgjyoU

Notes:
Any map that allows a player to walk through light blocks, if that player can exit and save during that position, reloading will cause the game area to be altered. I can see this affecting many maps that use light blocks.

Report has mentioned structure voids are affected like this as well