Snow layers change light behavior with Smooth Lighting Enabled

What's Happening:
When snow layers are on top of blocks, and Smooth Lighting is turned on, some blocks aren't lit the same way as the ones without snow layers on top.

What I Expected:
I expected the lighting to be the same across all the blocks

What I know:

• It is caused by the shading of Smooth Lighting; as turning it off resolves the issue.
• The effect is more pronounced when there are opaque blocks right next to the snow layer, but they are not mandatory.

Screenshots Attached:
Yes.