Bug had fast+, pm+, 5.9+, dev+, qa+. After change to modify all acks except qa were lost. I saw this behaviour on more bugs. As an example see: https://bugzilla.redhat.com/show_activity.cgi?id=846814 The developer doesn't even have permission to change state of these acks, therefore bugbot is broken. Please fix it asap.
*** This bug has been marked as a duplicate of bug 838095 ***