With the next update’s anisotropic filtering system, shelf blocks are affected by a texture bleeding issue that no other blocks are subject to. This is a direct result of their atypical texture mapping system, which other blocks do not use.
In specific, all four textures for each shelf variants exist on a single 32x32 image file, rather than four individual 16x16 image files being used.
How to reproduce
A resource pack that makes the bleeding more obvious is attached to this ticket.
Apply the resource pack
Look at the right hand side of a shelf looking downward
Expected results
No texture bleeding.
Actual results
There is a thin blue tint on the texture edge, which obviously should not be there.
How to fix
A resource pack that fixes this issue entirely is attached to this ticket - the shelf textures are split into four individual textures, and the models are updated accordingly to select and map these textures onto the mesh correctly. Mojang have my full permission (and strong encouragement) to use these resources to fix this issue.
Note that this is still noticeable even without a resource pack. Here’s the boundary between two stacked birch shelves: