I have a group made up of Casetta plug-in dimmers that has been misbehaving since the 2.2 update. This group is used in Motion Lighting, and at least once a day now, when ML turns the group off, the master group switch turns back on after a fraction of a second, even though all member dimmers are correctly off (in reality and also reflected in the device page).
This did not happen prior to 2.2, and now happens about once a day. Did anything change in the Group app?