I was able to duplicate the problem with the help of Arti Kashyap. . Signing in with user id and password to activities.sap.com causes this issue as opposed to utilizing SSO. When clicking on the avatar it does nothing. When logging in with a specific user id and password it displays activities but the avatar and sign in or sign out does not work. It only works for SSO user.
Thank you and I will add this problem to the Known Bugs List.
with kind regards,