Some of my Zigbee lights self-activate during the night

Install the Audit app, this app logs “everything”. And no need for creating flows.
See

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Unfortunately this can also mean a flow changed the dim level.
Or, in case you use f.i. a Hue hub, something on the hub commanded the light;
Very annoying because it doesn’t reveal the “guilty” flow.
One of the reasons I add log cards to many of my flows.
But the Audit app does a great job as well.