The team has learned that there is a known bug that causes SIMply Crafted (Fabrication) Freelancer gigs to not complete. After you send the item to the client and get a response back, if the "Send item to client" task doesn't complete, you may cancel the gig and count it as complete. It won't register for the Master Maker aspiration, so you will need to track the five gig completions yourself. Once you have completed 5 gigs, including sending each one to the client, along with everything else for the aspiration, you can use a cheat to complete the aspiration. If you don't know how to do that cheat, please refer to the Cheats page here on Carl's Guide.
I am updating the rules and second post to reflect this.
Edit: There is a small amount of evidence that suggests candle-making gigs do register while fabrication gigs do not.