wkWebView, Trusted Domain, and Autofill/KeyChain Issue

We have been searching for almost one year for answers as to why wkWebView using an Entitled Domain will allow Autofill with KeyChain to fill credentials, but will not trigger Autofill to store/save them. In other words, if users have previously stored credentials in Safari while visiting domain X, subsequent visited to wkWebView with entitled domain X will allow use of those credentials in wkWebView through the Autofill/Keychain dialogue. However, users cannot save/store credentials within wkWebView in Trusted domain X because the save dialogue is never triggered.