(I searched through a few similarly named issues and could not find one which exactly emulated my issue so I am posting a new one.)

Each time I log into my Minecraft world there are many blocks which will appear darker than they should be. They all have adequate light sources, and when I place a torch down and break it the shadow will go away, but only within the torch's lighting radius.

This issue will typically occur on prebuilt structures, and always the same ones. However, I have had a few instances where it would occur on newly placed blocks after I unload their respective chunks.
The issue affects some vertical faces and some horizontal faces.

Attached are some before and after screenshots of the glitch before I placed a torch down and after.