Darkness in daylight

After playing a few hours light dissapears completly in areas in the overworld even in the day. Mobs spawn and track you. When spamming the area with torches they only lit upp a few blocks.

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
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