So I have a recurring problem with the wired Nest Protect. I have the pathlight set to be permanently on, yet it keeps flashing on and off. It fades up and down on a slow 10 second cycle, which is actually quite dangerous if it cuts out when you're halfway up the stairs.
I've been through this on chat with support several times. I've also had the hardware replaced twice, but it's still doing it. The previous unit always did this, straight out of the box. On the current unit it worked as expected for about a week before returning to the flashing behaviour. Not sure if a related issue here but it seemed to happen at the same time I added other smart plugs on the Home app.
As this keeps happening even when the physical unit has been replaced, the problem lies elsewhere. So I'm surprised that I can't see anyone else having this issue?