In the case of the shutter it could be a bit like a window which is banged by an air current against the frame. Although the energy is impressed only in one direction, toward the frame, the window will "bounce" on the frame.
Now imagine a spring impressing a motion on the window. The window will reach a certain speed, bang on the frame, and if the spring (in extended position) is not strong enough, the window will bounce back, immediately after the spring will push it again against the frame.
Another example would be a marble ball "bouncing" over a marble floor although marble is not elastic.