I printed the mesh interface before and after initilization. After initilization it tells me one side is "filled" with wall 7 and the other side with wall 7 ratio. Does that mean the solution without walls 12 and 13 is more correct and I should get rid of them by deleting the mesh interface (contact region)?
Edit: I found out that by deleting the mesh interface I get rid of also the wall 7 and wall 7 shadow. Should I in that case check the "Matching" option at the "Interface Options" ?