Created Unassigned: Authentication to on-prem SP using multiple auth types [65179]

Attempting to authenticate to on-prem SharePoint (2013 or 2016) doesn't seem to work if web application is configured to use multiple authentication types (Windows + SAML in our case).

I believe SPCB code should include )"X-FORMS_BASED_AUTH_ACCEPTED", "f") header as discussed here: https://msdn.microsoft.com/en-us/library/office/hh124553(v=office.14).aspx.