"Often"?  What are teh other possibilities?  What does ""power through fixture" curcuit" mean?  In 30 years of remodeling I've never heard that term.

I have the same issue. The second I press the switch on the wall or power on via the app. The lights flicker on but immediately turn off. Has anyone found a solution to this yet?

I have the same problem too, any anwers yet

Same issue here. I thought it might be because the same light fixture can be controlled by another switch upstairs, but from what I'm reading that shouldn't be a problem.

Yes, its a neutral wiring problem. I followed the instructions exactly (being an amateur) and was having the same problem. I checked this forum and read the comment that it is the neutral wire. I had initially wired mine where I took one of the neutral wires from the the bundle in my box and connected it to the switch neutral wire, putting the rest back in their bundle. This is apparently wrong - I don't think the instructions were clear here. I fixed it by adding the adding the neutral wire on the switch (and the one I had I connected it to) back to the whole bundle. Now it works fine.