I had a similar problem with my 2011 North Country 29RLS. It has the 19' Carefree of Colorado electric awning. After only one month of ownership I noticed that the top two screws on the aft arm had started to pull out of the aluminum. The awning had not been subjected to high winds or heavy rain. The foreward arm looked fine.
Took it back to my dealer (Oliver's Campers in Norwich, NY) and they looked it all over and told me that they had seen this in one other North Country recently so they knew how to fix it. They consulted with me on possible fixes and we came up with steel backing plates for the aft arm screws. Fortunately in my model the screws come into the unit behind some corner cabinets so nothing shows. They used macine screws right through the wall into steel plates. That arm is not going anywhere now.
The problem was either poor design or poor workmanship on Heartland's part. The foreward arms were screwed into the wall studs and appear secure. In the case of the aft arms the wall stud was 2" away from where the arms needed to attach so they just screwed the arms into the aluminum siding, put in an extra screw for good measure, and caulked it like crazy.
Design problem or workmanship issue? Take your pick. The designer knew that the optional electric awning would catch one stud but not both with the given 19" width. The installer knew that they caught one wall stud but not both when they put it in. Heartland shipped it anyway.
Oliver's solution now has a backing plate and the plate is also screwed into the wall stud. I am very happy with the dealer's service under warranty. Had the problem come up after the warranty expired I might not be so forgiving of Heartland's part in this. I will call customer service and chat with them about this, but I am still happy that I bought a Heartland product. As my dealer told me, "There is no such this as the perfect RV."