The bug
Similar to sandstone walls (MC-137957), the top face of blackstone walls has the side texture instead of the top texture.
Linked issues
Attachments
Comments
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w05a.
Can confirm in 21w05b.
Can confirm in 21w05b.
Can confirm in 21w06a.
Can confirm in 21w07a.

Affects 1.17.1

Affects 1.18

Affects 1.18.1

Affects 1.18.2

Affects 1.19
Can confirm in 1.19.2.

Can confirm in 23w07a.

Can confirm in 23w14a

Can confirm in 1.20.5 pre4.

Can confirm in 1.20.5.
Can confirm for 20w46a.