Foreman 1.9 odd user issue

OK, it's a busy day for me and Foreman/Katello oddities…

I've just been sorting out proper role-based permissions on our Katello
installation, and found that if I made it so that a user was only an
"Administrator" by virtue of being in a (external) group, the user in
question disappears from the "Users" page in the web GUI.

I can make the user disappear/reappear by fiddling with the database like

update users set admin='t' where id=4;

update users set admin='f' where id=4;

When the user has their admin property set to 'f' the user disappears, but
can still login and has all the expected rights.

Anyone seen this?