The bug
Oak Sign, Acacia Sign, Jungle Sign and Dark Oak Sign have a transparent bottom, the Spruce Sign has the missing texture (pink and black boxes). Birch Sign is fine.
How to reproduce
Place the signs listed above in an item frame.
→ ❌ They have a transparent bottom/missing texture
Related issues
is duplicated by
relates to
Attachments
Comments
migrated
[media][media][media][media]
migrated
fixed in 18w46a due to the fix of MC-139000
FaRo1
These two issues seem unrelated to me, especially since the other doesn't mention signs or misding textures. Did you verify that it's fixed?