Xcode – Setting the image on UIImageView changes the animation

I have a UIImageView that I wish to animate at the click of a button. But before the animation, I set its image. However, this image-setting messes up the animation. When I comment out the image-set, the animation works as expected.

        var busFrame = self.newBusView.frame

        let sourceFrame = self.buttonA.superview?.convert(self.buttonA.frame.origin, to: nil)

        busFrame.origin.y = sourceFrame!.y
        busFrame.origin.x = sourceFrame!.x

        self.newBusView.frame = busFrame

        //the following line messes up the animation
//        self.newBusView.image = UIImage(named: "back_blue")
        
        UIView.animate(withDuration: 2.0, delay: 0.3, options: .curveEaseOut, animations: {

            busFrame = self.newBusView.frame
            let desstinationFrame = self.buttonD.superview?.convert(self.buttonD.frame.origin, to: nil)
            busFrame.origin.y = desstinationFrame!.y
            busFrame.origin.x = desstinationFrame!.x
            self.newBusView.frame = busFrame
        }, completion: { finished in
            print("Done!")
            //same thing happening here
            //self.newBusView.image = UIImage(named: "Background 1")
        })

Also note that the buttons are in separate Stack views (hence the need for superview?.convert)

UPDATE:

So it was noticed that whenever I have a button.setImage() the positions go wrong (Even if the button has nothing to do with the animation). But instead of setImage, if I use button.imageView.image = something, then it has no side effects on animations. What is happening?

Expected:

Actual: