One problem I recently came across with a client, is that when I opened IE and typed in the url of dynamics crm, after redirecting me to ADFS log in and typing in credentials, it took me to the mobile forms.
Fortunately, this has an easy fix: Just replace "/m/default.aspx" with "main.aspx" in the url, and the regular forms show up.
What is not so fortunate, is that the fix is not permanent, the workaround may have to be executed over and over again. I believe the problem is somehow prevalent in ADFS configurations, but I don't know how or why yet