@User: I'm going to sunset the use of the GDS generation method I put in place for you to make sure that certain mask layers would reach the sides of a standard cell bounding box. I have in place now a more reliable method with an operator called "mask-hints". This allows additional mask geometry to be added to a cell in the form of a property key:value pair. There are now "mask-hints" operators for all of the layers I think you are using in this way (NSDM, PSDM, and NCM). To use it, you need magic version 8.3.111 (which I am pushing today), and you would add the property in a cell using the command, e.g.,

property MASKHINTS_NCM "_llx lly urx ury_"

in internal unit coordinates.