How is it possible that Energy reports 65kWh power consumed in a day by a <10W light switched on twice for a few minutes?

@K_S, there are already several posts in the Homey Energy — Public Beta Megathread topic, with problems similar to yours, like mine:

Instead of an upward peak, I had downward peaks (pls. have a look at the screenshots in my linked post).

According to @Robin, an Athom employee, it is supposedly the device that is giving incorrect values and there is nothing Athom can do about it:

As you can see in the linked post I also had this problem with Z-Wave devices, a Fibaro Double Switch (FGS-223) and an Aeotec Smart Switch 7 (ZW175).
In the Energy Topic, other users also have such problems with Zigbee devices. That’s why I’m not sure that the issue is really caused by the device.

To be honest, I don’t have a solution for this problem either and I don’t think that resetting the consumption is a permanent solution.