I have several SNZB-02D devices and about half of them goes regulary offline. As they go offline, the display shuts off, but if I gently tap it, it lights up again. The display sometimes blinks as I slide it out or into the wall mount. Anyone else got this issue?
This looks like a hardware defect in the SNZB‑02D. When the device goes offline and the display turns off, but tapping it brings it back, that usually means the internal power contact is failing. Several users have reported the same behaviour. I’d recommend requesting a replacement from Sonoff, as affected units tend to get progressively worse over time.