It is a pretty random grouping of lights, not even all the same tech and they all say ‘turned on by Home Assistant Cloud’. Also, there is no other event that happens that would have triggered as can been seen in the log.
It happened for me also, the problem was from the Google Assistant, I called the assistant and then I aborted the command but GA had another idea I checked the logs after and the time stamp is the same.
You can check the Google Assistant logs here: https://myactivity.google.com/ (filter for date and Service).
Having the same issue for about two weeks now. Random triggerings by Google Assistant, typically at the same time each day. I will be doing nothing and then boom lights turn on. Usually the same 10 lights. I have no automation set up for this. Checked Google and it does not even have an activity in the log. Home Assistant DOES have an activity logged, but it is logged by Home Assistant Cloud and not Google Assistant. Has anyone had any luck figuring this out yet?
I just discovered my system randomly doing this too. Eventually tracked it down to an Alexa routine that was turning on lights at sunset. I certainly don’t recall setting up this routine and it only started happening in the past few days