“Same net spacing” means that the copper to copper distance within the same electrical net is too close to be able to produce according to the Gerber files. Since it is within the same net, the DRC (design rule check) in the customer CAD software doesn´t alarm for this failure. It is important that the customer set the limits correct when starting a new design. Minimum copper to copper distance is normally set up correct, but they miss to set the same value when within the same net. It is not a very big issue, but it causes delay and unnecessary technical questions.