It's exactly the same. I'm looking for a solution to this.
It works normally in UIWebview, but it is a be thin success in WKWebview. I've searched a lot of documents, but I haven't solved them.
I'd like to get help from other developers.
But in my case, touch id and face id are not working both.
I still have the same problem on iOS 12.3.1.
This is affecting me as well. Autofill works when using FaceID or by tapping the key icon first, but never works when selecting an autofill suggestion followed by TouchID. TouchID seems to authorize fine, but nothing is sent to the HTML input field.