I recently installed 3 switch side-by-side (all independently from one another). The connection is fine and the lights turn on. The only issue is the lights wont stop flickering. It gets worse if the intensity is higher, when i lower it it gets better for a while and then it goes back to flickering.

I will say that the connections are a bit shady (the neutral wire from the switch was put back in the load of the switch, along with load that goes to the lights)