Weird UIPageViewController + drag bug

Did you find any solution yet? I'm having the same issue (with vertical PageViewController scrolling). Really want to implement Drag & Drop, but it always glitches to a blank screen ...

I have this bug yet (iOS 12), did you find a solution?

I found workaround for this, you need to set pageviewcontroller datasource delegate to nil during drag, and then set it again at end dragging.

    // WORKAROUND
    // When Dragging to edge of the screen in UIPageViewController, page controller switch page to a blank page

    func collectionView(_ collectionView: UICollectionView, dragSessionWillBegin session: UIDragSession) {
        if let pageController = self.parent as? UIPageViewController {
            self.tmpPageViewControllerDataSource = pageController.dataSource
            pageController.dataSource = nil
        }
    }

    func collectionView(_ collectionView: UICollectionView, dragSessionDidEnd session: UIDragSession) {
        if let pageController = self.parent as? UIPageViewController {
            pageController.dataSource = self.tmpPageViewControllerDataSource
            self.tmpPageViewControllerDataSource = nil
        }
    }

Code Block 
class BuglessPageViewController: UIPageViewController {
    
    private var preventScrollBug = true
    
    override func viewDidLoad() {
        super.viewDidLoad()
        scrollView.delegate = self
    }
    
    override func setViewControllers(_ viewControllers: [UIViewController]?, direction: UIPageViewController.NavigationDirection, animated: Bool, completion: ((Bool) -> Void)? = nil) {
        preventScrollBug = false
        super.setViewControllers(viewControllers, direction: direction, animated: animated) { completed in
            self.preventScrollBug = true
            if completion != nil {
                completion!(completed)
            }
        }
    }
    
}
extension BuglessPageViewController: UIScrollViewDelegate {
    
    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        preventScrollBug = false
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if preventScrollBug {
            scrollView.setContentOffset(CGPoint(x: view.frame.width, y: 0), animated: false)
        }
    }
    
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        if !decelerate {
            preventScrollBug = true
        }
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        preventScrollBug = true
    }
    
}
extension UIPageViewController {
    
    var scrollView: UIScrollView! {
        for view in view.subviews {
            if let scrollView = view as? UIScrollView {
                return scrollView
            }
        }
        return nil
    }
    
}

Hey there, future programmers!

After playing with disassembler for a while trying to find the root cause of this old bug I have found that it is probably "autoscroll" logic, clashing with UIPageViewController paging logic.

In my case, disabling the autoscroll using aforementioned hack with dataSource = nil is not plausible, since I want exactly what autoscroll offers in drag session.

The only solution that I have found is to opt out of UIPageViewController completely and to implement my paging view controller using plain old UIScrollView with isPagingEnabled = true.

It is a bit of a complex task to implement dynamic page loading this way, but should not be a roadblock for the experienced developers.