I wrote what I thought should be a simple rule: code is above. The goal is that when one of 3 switches is turned on, a routine triggers that turns all 3 lights on. Originally, I had a second branch in the tile to do the opposite—turn them all off in concert when one was shut off. But sometimes, it triggered a loop where the lights all turned on and then off every few seconds.
I broke it into two rules—one for on. One for off. But even so, sometimes they just all turn on for no reason.