[Carl n Susan]

Montana went cheap on the vertical panel starting in 2011. It used to be a much thicker panel. The thin panel they started using flexes with the front end and causes the staples holding the shelves to pop out. They also made the panel a tight fit to the floor so it breaks when the front end flexes.

While some amount of frame flex is expected, ensure that yours is not excessive indicating the welds have failed or the exterior wall has separated from the frame.

The solution to the cabinet problem (assuming you don't also have a frame flex problem) is to have Montana (via your dealer) fix it correctly. They have a 3/8" or 1/2" panel replacement for the vertical closet wall. It doesn't flex/break and it provides better support for the closet shelves. Mine had the same problem (along with excessive frame flex) and that is how the dealer repaired it.