My VW used to do just that exact same thing...until I replaced the control arm bushings...couldn't even do an alignment prior to replacement because they were so worn, the alignment jig couldn't get the car to track properly!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car