I recently encountered a single sign-on issue following a password reset.
On resetting the windows password I was able to access the workspace tile screen, and see my models, however when I tried to open a model or access Manage Models, I was redirected to the normal Anaplan login screen.
With help from Anaplan support the issue was found to be the result of cookies which had retained my original login details.
I tested this issue by opening an incognito browsing session in Google Chrome (CTRL+SHIFT+N) and using the incognito session I could access my model with no issue. Therefore the longer term fix was to clear cookies and the SSO login functionality was restored.
If you encounter SSO login issues following a password reset it is worth trying this approach in the first instance.