High standby power usage by smart lights solution?

No idea what you mean by that, as opposed to behind ???

I mean that the dimmer controls the light. So if the dimmer is off, the RGB lights don’t get any power supply. But I don’t know if he meant that.

Yes, @jazzyisj is talking about an extreme case of your example.
He’s saying that his dimmers are taking a lot of power but for some reason, even more when they are off than when on (by a significant margin. .

Jason, I’m just not sure about this, is it just the one device or do other instances of the same dimmer / lamp package exhibit the same characteristics ?
Could it just be a calibration issue ?

When I first started out with dimmers I did a set up on a workbench and measured ‘actual’ current consumed. (as I said, I generally use Ikea Ledare bulbs but even those (with the same model type) have varying consumptions (in tests, - 6% to +9% of stated). My tests ‘generally’ bore out what you’d expect but as I generally run below 100% (and given I2R) that saves power too.
[I know you know most of this but the explanation is so that anyone reading has this as a background]
I’d be intregued to hear the results of your tests, and if ‘verified’ alert people to this issue to avoid that equipment combination.