The bug
When a solid opaque block is placed on a surface, a small shadow is cast into the surrounding area. However, a slab does not create such a shadow.
This effect can be observed on numerous other blocks, which causes them to look weird and out of place.
Related issues
is duplicated by
Attachments
Comments

Is this new to the snapshot lighting system, or has this been an issue for longer?

Currently not at a computer, but I'm able to reproduce it on bedrock edition, so it's probably been around for longer.
Can confirm for 1.13.2.

pulpetti only say what versions it currently affects not past versions all your doing is blowing up emails

Affects 1.16.1

Affects 20w27a

Affects 1.16.2

Affects 20w45a

Affects 20w46a
Can confirm in 20w51a.

Affects 21w03a
Can confirm in 21w05b.

Affects 21w06a

Affects 21w11a

Affects 1.17 Pre-2
Can confirm in 1.17.

Can confirm in 1.17.1.

Affects 21w38a

Affects 21w40a

Affects 21w41a

Affects 21w42a

Affects 21w43a

Affects 1.18 Pre-1

Affects 1.18 Pre-3

Affects 1.18 Pre-6
Can confirm in 1.18.1.

Affects 22w11a

This now affects mud.

Thank you for your report!
After consideration, the issue is being closed as Won't Fix.
Please note that this is not the same as Working as Intended, as this bug report correctly describes behavior in the game that might not be the intended or desirable behavior, but it will not be fixed right now. Sometimes, this is because the issue reported is minor and/or impossible to change without large architectural changes to the code base.
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