Sun rays illuminate dark areas in deferred rendering

Steps to Reproduce:

1. Create a world with a PBR enabled resource pack and enable the "Render Dragon Features for Creators" experiment;

2. During daytime, Find and enter a dark cave with no access to sun light.

Observed Results:
The sun rays disregard the terrain and illuminate the dark caves. Interestingly, the underground still gets affected by leaves on the surface, leaving tree shaped shadows.

Expected Results:
Sun rays aren't present in areas with no access to sun light.

Screenshots/Videos attached: Yes

Notes: The attached resource pack only enables PBR and nothing else, all components are using their default values.