(hack since Issues are not enabled on this project?) Looks like G85 - probably slots? are not supported as is. I am facing this issue with my KiCad project which uses those. It looks like some German guy has worked in that direction - see https://git.phoerauf.de/VT7/gerbmerge-utils/blob/master/gerbmerge-1.8/gerbmerge/jobs.py Only problem is that his code is based on the original 1.8 soursce I wonder if there is a chance that one day somebody would merge this 1.9 branch with his G85 progress