This error shows when InAppBrowser crashes when attempting an image upload (when you select camera/ video option in IOS menu).
I also had to add camera permissions in the info.plist file, however i have no idea if its working as InAppBrowser crashes just before that point. here is the error:
2018-01-23 19:14:53.873 appname[312:32242] Warning: Attempt to present <UIImagePickerController: 0x14480e800> on <UINavigationController: 0x144240600> whose view is not in the window hierarchy!
Maybe something like this? https://stackoverflow.com/questions/28379327/ios-warning-attempt-to-present-viewcontroller-whose-view-is-not-in-the-window/28379914