Bug or Feature in the Team's email List?

When looking at the page showing me, as the team leader, the email addresses, I see a few emails with some magic key appended.

All those addresses have the form
@name@service.tld_927fde612a765def17382fde9234facd
whereas normal addresses have the form

I tried those magic keys and found that I can log in with them, at least with all, but one. All those guys have the status 'Verification waiting', that one where the key does not work, has crunched a long time ago.

For my team the users with that feaature are the following:

http://einsteinathome.org/account/55216
http://einsteinathome.org/account/55298
http://einsteinathome.org/account/
http://einsteinathome.org/account/55391
http://einsteinathome.org/account/55405
http://einsteinathome.org/account/55433

If you are a team leader, then replace the xxx by your team's id, and then check the email adresses.
http://einstein.phys.uwm.edu/team_email_list.php?teamid=xxx

BTW: Two guys joined today and the # of users is constant at 281, should be 283 ... but this is a different old bug :-(