also... every turbo will flutter to a point.. if I "floor" it at 2,500 RPM.. and let the turbo spool a little bit and run 1psi or 2psi and let off. the BOV does not open even really loose.. and causes a small quiet flutter. ever listen to a car with HUGE turbo?! it will naturally flutter slightly.
What will damage it is flutter from high boost.. like running 15psi letting off and hearing a LOUD flutter
Blow off valves will also flutter when set to a very light setting they will open and close quickly.
In addition external wastegates will flutter as well.. same as the BOV with it opening and closing