Since 24w40a (1.21.2 Snapshot), entity shadow and vignette now gradually fades in/out on light level changes, for example, when a mobs/player is on unlit place or night time, then starting to walks toward lit place or sun start to rise/become day time, the shadow will gradually fades in and the vignette will gradually fades out, this is not the case on Bedrock Edition.

Steps to reproduce:

• Daylight cycle

1. Give yourself a repeating command block, changes the redstone to "Always Active"
2. Paste this to Command Input box: /time add 40
3. Observe

• Weather cycle

1. Set the weather from clear to rain or thunderstorm
2. Observe

• Unlit/Dark places

1. Give yourself a Night Vision effects, otherwise you wouldn't see the vignette transition due to being dark
2. Enter an unlit/dark place (like caves, dark forest biomes, etc)
3. Observe

Expected results:
Entity shadow and vignette gradually fades in/out on light level changes, like in Java Edition.

Observed results:
Entity shadow opacity stays the same, and vignette does not appear at all.