Blueprint url_prefix misconfiguration causes wrong route path

Blueprint routes accessed at wrong path due to url_prefix being prepended. Route defined as /profile with url_prefix='/users' is reachable at /users/profile not /profile. Double-prefixing occurs if prefix set on both Blueprint and register_blueprint().

Set url_prefix either in Blueprint constructor or in register_blueprint(), not both. Verify actual route path with 'flask routes'. Remember prefix is prepended to all Blueprint routes.