Automatic change admin to subscriber

Hi, maybe a strange question, but here it goes.

Since we have membership installed and new members automatically get the subscriber status it has happened several times that the admin status also gets changed automatically to subscriber.

We have two admins and on Saturday both of us were downgraded to subscriber and could only restore it by adjusting it through ftp in the database. This morning again one has been set back to subscriber. We have not done anything else/new but I think there iOS a coincidence as it started exactly when we installed Membership.