If the D3V’s LED occasionally flashes red even when the device is switched off, there’s usually a small residual voltage still present.
This can happen when the D3V is connected to a wireless or multi-outlet power strip that doesn’t fully disconnect the power supply.
You can easily check this by plugging the D3V directly into a wall outlet. If the LED no longer flashes while the device is off, the blinking is related to the situation described above.