Same issue in MC-266777 (Which found that i tested seen possible).
When non waterlogging copper grates, The skylight passes through them but if they were waterlogged doesn't passing lights.
World Type: Overworld Infinite
Steps to reproduce
Create a new Infinite world with 1.21 Experiments
Locate to Sea/Ocean biomes
Place copper grates start at bottom to end of top in deep sea
Take bucket to remove waterlogged copper grates
wait for visible to dark brightness
Observed Result
❌ The non waterlogged Copper Grates can allow skylight to pass through.
[media]Expected behavior
non waterlogged Copper Grates can should not allow skylight to pass.
Linked issues
Attachments
Comments 3
migrated
This is not the same issue as MC-266777. That report says that sky light passes through waterlogged copper grates. This report says sky light passes through not-waterlogged copper grates. The behavior reported here is the same for glass. I am not sure why you would think it is a bug. The behavior reported on MC-266777 does not occur in Bedrock.