Authenticated feed for protected comments not working

For some reason using the authenticated feed does not work with User Access Manager with the following syntax:

http://username:[email protected]/members-area/feed

The feed works fine when I mark it as not protected and use the following syntax:

http://example.com/members-area/feed

Is this on purpose or can anyone help?

https://ww.wp.xz.cn/plugins/user-access-manager/