I know nothing about GRBLGRU but suspect that your problem may be connected with the units used.Is there a G20 or a G21 at the start of your program?I have seen similar screenshots when an Imperial file has been imported into a piece of software that defaults to metric.When you open your .dxf,how far from 0,0 is the lower left corner?With any luck a GRBLGRU expert will be along to swiftly get to the root of the matter.