I got a weird one.. I've been using mirror me for awhile to turn other lights on and off with a physical switch and it works fine.
I just added a new bulb to come on and off with my dining room light (hampton bay fan controller). I control that light mostly with a pico and button controller.
If I turn the dining room light on via the web GUI or Alexa, my mirrored bulb works. If I turn the dining room light on via the pico and button controller the mirrored bulb does not turn on. It will turn off via mirror with the pico however.
I've got this setup the same way in another room with a pico and a zwave switch, and it works as expected with the same settings (dim 100, fade 0).
Button controller:
Mirror app: