I wouldn't expect everything to be calm two hours later if they were being robbed....?
Mine often go on mass orientations after a day or two without sun. The flights are stunning to watch - huge buzzing and lots of activity (and I still think uh-oh, did I miss a QC?). A mass of bees fly in front of the hive, facing it. A lot of the ones that do head skyward do so in a bit of a spiralling, random flight, not that of a practised forager. The foragers are still whizzing in and out, on their beeline, amongst all the apparent chaos. After half an hour or so, the flight ends and only the foragers are flying. It often happens that several colonies will undertake orientation flights at the same time...