Interactive cloth seems hard around attached collider

Hi (and sorry for my bad english)! I'm trying to simulate a goal net with Interactive Cloth, but seems to act weird around the colliders that support the net.

The net is a simple mesh: four sides of a subdivided cube, textured to look like a web. When I enable the attached colliders (two for the goal frame, and three for the ropes which support the back side of the net), at least 3 vertex away from each collider seems to be "hard" (stiff), as if they weren't part of the cloth. (I was going to upload an image but Unity Answers always show an "error parsing file" message). I'm now playing with the bending and stretchness parameters, but they didn't seem to cause any difference. Someone knows if there's a parameter I'm missing, or any other solution?

Thanks in advance!