Actually, its acting as I would expect. Comparing the variable places those objects into the sol, and with the mouse is over as a sub-event the sol is carried over.
I think what you need to do is have the mouse is over as your first condition. You can then filter from the pvs that way.
+ MouseKeyboard: Mouse is over Sprite
+ Sprite: Value 'Variable 1' Equal to 3
-> Sprite: Set opacity to 50
-> Sprite: Set angle to 45