Items are dark

I have been jumping from snapshot to snapshot in my survival world, making sure to optimize every time I move to the next snapshot. However, in this new snapshot, all items and mobs seem to be dark in colour after I moved from 20w21a to 20w22a. I don't know whether this is a bug or because my constant jumps from snapshot to snapshot caused something to glitch, but it might be worth looking into.

 

Thank you for your time,

A Minecraft Lover