I have a board with DRC spacing set to 8mil trace to trace, trace to pad, and pad to pad. I have these traces routed on the top and bottom layers, inside of a ground plane with isolate set to 10mil, and the back off or cut out spacing = i.e the isolate seems to be cutting back 12mils, and when I run DRC, I get all kinds of clearance errors, when there is clearly 10 to 12 mil spacing, even If I change the isolate to 0, I still seem to get the back off or cut out spacing of 12 mil, and still get DRC errors with 8mil settings. Is there some setting I am not aware of, or does DRC not function as intended?