Do not use the elseif but again a normal if while checking the devices. Although not sure it is really the solution. This kind of sync is asking for trouble: the update of 1 switch will trigger the update of another. Which can trigger the first switch again if domoticz is not changing the device ...

Hey, I have a script that sync's 2 switches, works fine but after 1 or 2 weeks the switches bigins to flicker (on/off) very fast. I have to reboot the pi to stop the flickering. Does someone have a solution or other script? commandArray = {} -- variabeles local Switch1 = 'Firstfloor' local Switch2 ...