No its not the mesh for the collission itself that is the problem, but which joint it is “parented” to.
Let me put it this way. This is the rig for the knee from the previous topic
https://forums.ragdolldynamics.com/t/issue-with-rig-after-baking-simulation/1050/9?u=ll_ll
There was the knee joint controling the marker and therefore the collission shape like in this pic
And the IK joints rotating the knee/fibula mesh in the correct way like here, which are not part of the sim and therefore have no collission shape.
So the problem is, if that part is colliding with something, it will go through the knee/fibula mesh.
Hope i could make the issue clearer. English isnt my native language