When light source block is outside the player's camera, point lights no longer shine in Deferred Technical Preview.
At least this is happening since 1.20.60.24

(How to reproduce)
1. Import the PBR resource pack containing the light block textures into Minecraft Preview
2. Create a world with Render Dragon Features for Creators experimental enabled
3. From the settings screen, switch to Deferred Technical Preview
4. Place one of the light source blocks in front of the player
5. Remove the placed light source block from the player's sight.
The point light of the light source block should have disappeared unnaturally.

(Expected result)
Point lights are rendered even if the light block is not in the player's field of vision

Update (2024/01/24)
This issue has been fixed in preview 1.20.70.20.