The Bug:

In 26.1 Snapshot 11, the textures of the brown, gold, and pepper rabbits were updated to be consistently shaded with white, patched, black, toast, and killer rabbits. However, this update missed another inconsistency- one that appears to have been a bug from the start. The tails of the latter group seem to be broken or unfinished.

This “Unfinished” group has a few noticeable issues- not only is their tail texture different from the other group, its different from their own babies, which the babies of match the more detailed tail group.
The unfinished tails also have very flat shading and strange borders and lines. It looks very unintentional

I’d expect all the tails are meant to be the same, using the texture thats more detailed and more like the tail all the baby rabbits share.

The images attached add the best comparison!