

I can't figure out where this shading issue comes from. (please read description)
The affected faces are planar, normals are reset and correctly oriented.
No matter what I do, the shading abruptly cuts like this on both of those "fluff strings". They follow the same geometry as other "fluff strings" on the very same object, but only those 2 in particular are shaded in this weird way.
Resetting crease doesn't fix it. Clearing sharp doesn't fix it. Doing both of those at the same time doesn't fix it. Adding a loop doesn't fix it. Hell, when I apply subdiv modifier and try rearranging the geometry manually, I can't get rid of this anomaly no matter what.
I'm planning to rig, pose and render the model, this is a part of a bigger piece. I want to avoid leaving such weirdness on it.