It's because the shape of your animation changes in each frame which affects the mouse cursor hit detection. You need to place a fixed round shape on top of everything (for example a Button instance with a circle in the hit frame).
Also, it seems to me you don't need a main timeline with more than one frame. But if you really need more frames, make sure to run a check so you won't add the same type of listener to the same instance multiple times. Like this:
_this.frame0Started = true;