Tangent_Turner's fix didn't work for me and some other people, so I decided to try and fix it myself. I would have just corrected his for him, but his description gave the impression that he did more than just removing the function that caused her to stop buying them, and I didn't want to try to sort that out if he added things, so I just went in the GECK and removed the function lines related to owning the settlement in her two melon dialogue lines. Worked for me, so hopefully that was the fix.