I’m not sure what the exact rules are, but could you “intend” to live there and then change your mind. Maybe even start to move your “stuff” there and then change your mind? Or “intend” it to be a second home and change your mind. Is there a law that says you have to owner occupy the property for a set time?
(I assume everyone realizes this discussion is for obtaining a mortgage and has nothing to do with claiming it as a rental property on your taxes.)