The normal procedure here in the forums is to upload attachments to your posting. Include the post processor file, the G-code file that is generated by that post processor, and a G-code file that reads the way you want it to read. These can be attached as a ZIP file if needed. Then someone can knowledgably help you and not just be making lots of guesses. If the problem is related to the Machine Control Definition or the Toolpath Parameters you are setting inside MasterCam, you may be asked to attach some screen shots of your actual settings.