APM replacing ADFS proxy 3.0 : different behavior based on user agent value

So, silly question first - why do you want to keep forms-based authentication enabled on ADFS - period? Are you planning on allowing direct access to ADFS for internal users that will need to use forms-based auth instead of WIA?

Also, assuming you do need to keep both FBA and WIA enabled, have you verified that you have successfully performed the steps outlined in that article you reference?