Nope. I didn't use IntegratedWindowsAuthentication in my config.
The one thing that I did that was not in the guides:
I added a Default Path to my ACS.
Local Provider > Service Provider Settings > Assertion Consumer Service
Default Application Path: /sap/bc/gui/sap/its/webgui
I believe that most of our use cases will start with a URL that goes to my ABAP service first and then redirects to ADFS for the identity confirmation. However, for something like webgui I may use a DNS Alias that goes directly to ADFS first. When I do that, it redirects with just my server name, not a full application path.
https://adfs.abccompany.com/adfs/ls/idpinitiatedsignon.aspx?logintorp=https://abaphost/
So I put the Default Path to use when it does. It seems to work so I think I have that correct.