Why do bbPress forum users see Main Site login option in their admin bar?

After installing bbPress, and selecting the option to "Automatically give registered users the Participant forum role," I see that under Users in the dash menu of my main site, participants are now showing up as if they were users of the main site, and not just of the forums. Also, when admin users who are "Participants" are logged into their own sites, if they hover over My Sites in the admin bar, they now see their own site plus the Main Site, complete with a link to the main site Dashboard. It still asks them to log in, and if they don't have that info they can't log in, of course, but this seems to be not just redundant but unnecessarily confusing, and possibly even a bug. Is this supposed to be happening? Is there a way to configure this differently, so that users aren't left with the mistaken impression they can log into the main site?

**It may be that I have incorrectly attributed this to bbPress, although the reason I thought it was related to that plugin is because the Participant role is assigned through that plugin's settings. I am still seeing the login option for the main site while logged in as admin even when bbPress is disabled.