RPi GPIO relay interference with input
I've faced exactly the same problem and just before going insane, I found the root cause and the solution.

Your problem is that the edge detect is very, very, very, very sensitive for voltage spikes. You probably will see false detections even when you switch on or off other equipement in your house as well.

To overcome this problem, just put a 10ms sleep delay in your callback definitions and read the pin status again; if still same than perform action, otherwise it was just a spike. Capacitors can help, but have to be designed in a specific way so the timing is perfect, also they have a different loading and unloading behavior, so this is rather difficult!

Please have a look at: https://www.raspberrypi.org/forums/viewtopic.php?t=134394 for some real proper information! Hope you will succeed!