Sway-Away
Some owners of 2008-2013 Buick Enclave AWD vehicles may comment that while switching lanes at highway speeds, there is a slight rear-end sway feel, sometimes described as feeling like driving in a cross-wind.
Inspect the rear suspension components for damage/looseness, and inspect the rear toe adjustment bar bushings with the suspension loaded.
Use a pry bar and apply forward and rearward pressure to the bushings at the spindle end. Also test at the frame end.