I am not an expert but I have noticed my bees doing the same thing every day at the same time (2hrs before sun set). The hive increases in noise from inside, the number of bees at the entrance increases and then a few thousand of them gradually fly out and about for half an hour or so before returning. It’s as if the ones that have been cooped up inside the get let out for a bit of exercise or something like that. It happens every day at the same time and I have never read about this kind of thing happening in any of the bee literature I have seen. It isn’t swarming and it isn’t practice swarming. The bees seem content, the hive is only 75% full. The weather has been warm all month long and there is plenty of pollen coming in. The ‘golden hour’ is when they all go for a flight and it has been happening every day for the last month or so. Perhaps its a Portuguese thing, I don’t know