For sure, but it's also true that I've had the problem after the upgrade. And, belive me, it's really not funny to loose all the widgets in a couple of seconds. Moreover because it was totally unexpected.
I can say this: after the upgrade I always restart the system. This time, within a couple of seconds after the beginning of the restart (so it was still closing all the processes but the upgrade was finished) my network disconnected from Internet (and reconnect itself only some hours later). Il know this for sure because the phone, that incidentally I've had in the hand, lost the WiFi connection and suddenly connected itself to the 4G network.
So, could it be that within the restart a widget (I've forgotten, I've also the calendar in the list) tried to connect to Internet and, having found no connection, something went broken and corrupted everything?
By the way, the only broken package is idea, that I upgrade alone so it's something that I know.