Fix a CollectionView item animation while changing a device orientation

I have made an Onboarding View using a collectionView with 2 items.

When I change device orientation from landscape to portrait the second item being animated and visible within the first item screen borders.

You can see the problem here: https://cln.sh/sgypvH

How to fix the animation so when switching from landscape to portrait I could see only the first item content with a white background on the screen?

Here is my code for collectionViewLayout:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

    return CGSize(width: collectionView.frame.width, height: collectionView.frame.height)
}

Here is the code for willTransition:

    override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
        collectionView.collectionViewLayout.invalidateLayout()
 
        let indexPath = IndexPath(item: self.currentPage, section: 0)
        DispatchQueue.main.async {
            self.collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)

        }
    }

Please let me know if you need anything extra to help me to solve the issue. Thank you!