QML Drag crashes because of QQmlEngine is NULL

My application crashes when I try to drag an item with QML Drag and set its imageSource to the url of image controlled by an image provider. While the image is cached it works just fine, but when the image is not cached, QML tries to request it from the provider and crashes because internally the engine variable is NULL there.

Please see the attached QML file that reproduces the problem a slightly different way, but the crash is exactly at the same place because of missed engine, not because of missed image provider.