The bug
Unlike ladders (MC-199237), vines (MC-199239), glow lichen (MC-212305) and other flat wall attached blocks, sculk vein blocks are not mirrored from behind as one would expect.
How to reproduce
Place sculk on a transparent block, e.g. barrier, glass
For comparison (expected behaviour), also place glow lichen or a similar block nearby for comparison
View the sculk vein from in front and behind
Expected results
The pixels seen from the front would be in the same positions when seen from behind.
Actual results
They appear on the other side when seen from behind, in contrast to other planes.
How to fix
A very easy model fix - just check the glow lichen model to see how it does it. I'd recommend just using a simple "flat plane" template model instead though - example forthcoming.
Linked issues
Attachments
Comments 5
Can confirm in 22w16b.
Can confirm in 1.19 Release Candidate 2.
Can confirm in 1.19.2.

The issue hasn't been fixed completely. Up & Down faces are still not mirrored correctly.
[media][media]
Can confirm.