WebView doesn't show local files

On iOS 10.2, loading local html file in WebView 1.1 fails since 5.8.
Until 5.7.1 it worked fine.
I already checked, the file exists on the device and the path is right.
Loading Content from web (eg https://www.google.com) works fine.
After setting the right url the log shows that the url is changing to ""

WebView

{ id: webView anchors.fill: parent url: "file://" + fileManager.getPathHelp() + "/View.html" onUrlChanged: console.log("help url:", url) }

Application Output:
qml: help url: file:///var/mobile/Containers/Data/Application/88DB3A52-3CAF-4FA2-9FEC-BCFEDFAE79B3/Library/Application Support/myapp/help/View.html
qml: help url: