I am experiencing a similar issue in which we are using a SAML authentication mechanism in our iOS application. We launch an in app browser to perform the SAML authentication. Previously with uiWebview everything worked as expected. The user completes the SAML login, is returned to the application and the SAML authentication cookie was present in the application.
Now that we have updated to wkWebview, the authentication cookie is present in the in app browser, but is not present in the application itself.
Has anybody come up with a fix or a workaround for getting cookies to persist between WKWebview instances within an app?