Hi,
This behavior can be explained with 3850 were talking to RADIUS. As you issued ip http authentication local can be a Bug anyway. Does you user has privilege 15 on RADIUS ? Considering the command local is not taking efect for some unknown reason, with proper privilege on RADIUS you should be able to get in.
I´ve seeing this behavior among Cisco platforms where after upgrade user loses privileges.
Maybe this can help you:
http://wirelessonthego.postach.io/post/ios-xe-5760-3850-3650-webui-privilege-level-based-access-control
-If I helped you somehow, please, rate it as useful.-