Help Relax the rope when required

[Romahaaa]

You can specify category and mask for each control point in the path editor:

Right, I just forgot about it, the scene was set long time ago.

Anyway, I did everything as you described, checked docs again, but the jittering issue still exist.
I did that way:

Scene environment colliders - group 1 and don't have any collision mask
Pencil and Paper Clip - group 2 and have collision mask to group 15 (rope). I also tried to set to everything, but it didn't help.
Rope - group 15 and have collision mask to group 2 (pencil and paper clip)
   

but.. even if this will work as expected without jittering, I see another problem here - when rope falls onto pencil or paperclip, it will go through their physics colliders..

And the conclusion to all my tests - even combining 2 approaches - avoid rope point intersection with pencil/paperclip colliders and settings up the collision group and masks I still have this issue. Seems the problem is somewhere else