I posted on this topic a little while back, but I'm doing it again because these photos show more detail and I think this is a common contruction practice for Keystone with all of their trailers regardless of price point. The photos show out of order becaue of the naming and I didn't want to have to go back and rename them just to get them to appear in a different order.
The middle photo shows how Keystone builds the support for the cabinet and dresser drawer glides. A piece of scrap luan plywood is attached to the 1X2 with wire staples. The bottom photo shows the single screw that goes through the 1X2 creating a pivot point allowing the entire drawer assy to rock in the directions shown by the yellow arrows during travel. This eventually pulls the staples through the 1/8" luan and the result is a drawer that flops around in the cabinet or dresser, especially if it has much of a load in it.
The top photo shows an easy solution, a piece of 1/2" plywood attached to the 1X2 with screws. I used deck screws because that was what I had with me, but any type and length will work. A second scew placed anywhere through the 1X2 eliminates the pivot point and prevents the entire assy from rocking during travel.