This bug report is a parity issue with Java.
In the Java version, the light block is displayed when the player is holding it (like barriers). But in the bedrock, he is completely invisible.
Steps to reproduce:
- Take light block (/give @s light_block 1 15)
- Place it in the world.
- Hold a light block in your hand.
Light block invisible.
The light block will be visible when the player is holding it.