Smooth Lighting Issues: Blocks seemingly have shadowy lighting on surrounding block

Description

When having smooth lighting enabled, both maximum and minimum, the lighting projects a shadow on ascending/descending staircases. This can even occur with a light source next to the block surrounding. It seems that this affects certain sides; the block next to the stairs, slabs, snow-layers or even above full blocks, whereas above in the opposing direction is also affected. This occured even after reinstalling 1.15.

Scenario

Within this scenario, there is a block difference of 4 between the ceiling and stair. This can also occur to full blocks and at different heights.