(reply to @claude31 - not an answer but submitted as answer so code blocks are styled properly) The crash does not happen in all cases the code shared is executed. I’m not sure what the cases are that cause this crash because we cannot reproduce it. Based on logs, it seems like a lot of the crashes are happening with this code   @IBOutlet weak var borderLabel: UILabel! //from scene in storyboard ...    let anchorX = borderLabel.frame.width / 2    let anchorY = borderLabel.frame.height    let popoverPresentationController = tableViewController.setUpPopoverPresentation(     sourceView: borderLabel, sourceRect: CGRect(x: anchorX, y: anchorY, width: 0, height: 0))         popoverPresentationController.permittedArrowDirections = .up    present(tableViewController, animated: true, completion: nil) I did not show where setPopoverPresentationInfo() is called. I just included the function definition because it calls setUpPopoverPresentation(), and I shared all the places where setUpPopoverPresentation() is called. I think we use sourceRect with zero size as a default value. We don't get a crash every time we use a zero size because some places always use a zero size, and we can’t reproduce the crash in those places. What are the implications of setting a sourceRect with zero size? I don’t see much explaining how the size of sourceRect is used in https://developer.apple.com/documentation/uikit/uipopoverpresentationcontroller/1622324-sourcerect. Could you explain exactly how sourceRect is used? How does the size of the sourceRect affect the popover or sourceView? What is the difference between using the sourceView.bounds and using zero (or any other value) for the sourceRect size? Unfortunately, I can’t share our entire project, and these methods are called in different places. I know it may be difficult to see what all values are in the code snippets, but I’m hoping the issue may be apparent from what I shared. In the code you referenced:   let popoverPresentationController = dropdownTable.setUpPopoverPresentation(    sourceView: sourceView, sourceRect: sourceView.bounds.inset(.init(all: -5))) sourceRect is the second parameter name for setUpPopoverPresentation which is given sourceView.bounds.inset(.init(all: -5)). In the same code snippet, sourceView is another (the first) parameter name, which is passed sourceView as the parameter. The passed in sourceView is a UIButton of custom type with a normal attributedTitle set, sometimes a normal image set, sizeToFit() called on it, and other variables set for it as well. This (setUpPopoverPresentation) is called with the button as the sourceView parameter when a user taps on said button. Please see my original question for the setUpPopoverPresentation definition. If I can provide more information that could help (besides our entire project :) ), please let me know! Thank you!

(here is hopefully an easier to read response to @Claude31) It only crashes on iPad, but we have a lot more functionality on iPad than iPhone, so it's possible the culprit flow is not available on iPhone. We call setUpPopoverPresentation in several different places. Here are snippets of how it is called: // BorderedButton is a subclass of UIButton private let button = BorderedButton(   normal: ColorPalette.LiveMessage.messageButtonBorderNormal,   highlighted: ColorPalette.LiveMessage.messageButtonBorderHighlighted) ... let popoverPresentationController = messagePopoverViewController.setUpPopoverPresentation(    sourceView: button, sourceRect: button.bounds) // within a method for creating dropdown popovers with table views - sourceView is of type UIView    let popoverPresentationController = dropdownTable.setUpPopoverPresentation(    sourceView: sourceView, sourceRect: sourceView.bounds.inset(.init(all: -5)))   @IBOutlet weak var borderLabel: UILabel! //from scene in storyboard ...    let anchorX = borderLabel.frame.width / 2    let anchorY = borderLabel.frame.height    let popoverPresentationController = tableViewController.setUpPopoverPresentation(     sourceView: borderLabel, sourceRect: CGRect(x: anchorX, y: anchorY, width: 0, height: 0))         popoverPresentationController.permittedArrowDirections = .up    present(tableViewController, animated: true, completion: nil) guard let senderView = sender as? UIView else {    return   }       let sourceRect =    CGRect(x: senderView.bounds.midX, y: senderView.bounds.maxY, width: 0, height: 0)   let popoverPresentationController = optionsViewController.setUpPopoverPresentation(    sourceView: senderView, sourceRect: sourceRect)   popoverPresentationController.permittedArrowDirections = .up   settingsContactViewController.present(optionsViewController, animated: true, completion: nil) // sourceView passed in is a UIButton func setPopoverPresentationInfo(sourceView: UIView, sourceRect: CGRect) {   let popoverPresentationController =    setUpPopoverPresentation(sourceView: sourceView, sourceRect: sourceRect)   popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)   popoverPresentationController.delegate = self   popoverPresentationController.popoverBackgroundViewClass = KeyboardPopoverBackgroundView.self   view.setNeedsLayout()  }

We only see the crashes on iPad, but we have a lot more functionality on iPad than iPhone, so it's possible the culprit flow is not available on iPhone. We call setUpPopoverPresentation in several different places. Here are snippets of how it is called: // BorderedButton is a subclass of UIButton private let button = BorderedButton(   normal: ColorPalette.LiveMessage.messageButtonBorderNormal,   highlighted: ColorPalette.LiveMessage.messageButtonBorderHighlighted) ... let popoverPresentationController = messagePopoverViewController.setUpPopoverPresentation(    sourceView: button, sourceRect: button.bounds) // within a method for creating dropdown popovers with table views - sourceView is of type UIView    let popoverPresentationController = dropdownTable.setUpPopoverPresentation(    sourceView: sourceView, sourceRect: sourceView.bounds.inset(.init(all: -5)))   @IBOutlet weak var borderLabel: UILabel! //from scene in storyboard ...    let anchorX = borderLabel.frame.width / 2    let anchorY = borderLabel.frame.height    let popoverPresentationController = tableViewController.setUpPopoverPresentation(     sourceView: borderLabel, sourceRect: CGRect(x: anchorX, y: anchorY, width: 0, height: 0))         popoverPresentationController.permittedArrowDirections = .up    present(tableViewController, animated: true, completion: nil) guard let senderView = sender as? UIView else {    return   }       let sourceRect =    CGRect(x: senderView.bounds.midX, y: senderView.bounds.maxY, width: 0, height: 0)   let popoverPresentationController = optionsViewController.setUpPopoverPresentation(    sourceView: senderView, sourceRect: sourceRect)   popoverPresentationController.permittedArrowDirections = .up   settingsContactViewController.present(optionsViewController, animated: true, completion: nil) // sourceView passed in is a UIButton func setPopoverPresentationInfo(sourceView: UIView, sourceRect: CGRect) {   let popoverPresentationController =    setUpPopoverPresentation(sourceView: sourceView, sourceRect: sourceRect)   popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)   popoverPresentationController.delegate = self   popoverPresentationController.popoverBackgroundViewClass = KeyboardPopoverBackgroundView.self   view.setNeedsLayout()  }

Our team is going to be updating the links we use for deeplinking soon, and it’s very important to not break deeplinking in production. We are doing QA before release. But since iOS 14, when we start QA we have issues with deeplinking for around three days before it starts working.  Will Apple please provide us with some information about how often the CDN's cache is invalidated and what happens if the request for apple-app-site-association files fails? Without this information, we don’t know how the system works, if the issues we have in testing will impact production, and if our users will experience deeplinking not working. Deeplinking is a very important feature for our app, and our users’ experience should not suffer because Apple won’t share documentation with developers. I see in https://developer.apple.com/forums/thread/658454 that the user-agent string for the Apple App Site Association CDN bot is AASA-Bot/1.0.0, but there is still a lot of missing information about how the Apple App Site Association CDN works. Could we add the “Universal Links” tag to this post (and maybe remove the “Linker” tag if necessary)? Thank you!