Using Memberstack 2.0? This has been fixed. If you have a similar issue please make a post in the 2.0 community forum.
If you notice buttons and links are "disappearing" from your site, we have a solution for you.
Memberstack automatically hides profile links from users who are not logged in. Try creating an account or logging in, and the profile link should reappear.
Memberstack automatically hides logout links from users who are already logged out.