I have about 25 switches in my home and they are all connected to a SKY broadband router.
Recently some have stopped switching as programmed, i.e. they don't switch when they are programmed to do so, some are set up as masters and are switched in scenes. All have worked fine for nearly 2 years until now.
Maybe my question is stupid, but you checked the scenes, or? Your devices are still listed inside? One time i had the problem that scenes still existed, but was empty after i relearned a switch.