Was flying US FLL-PHX. Boarded but then captain said that maintenance had to check something as a light was on in the cockpit. Long story short that involved disembarking and boarding a couple of times, a total of a 5 hour delay, US headquarters being contacted about the light, Airbus in France being contacted about the light, and a final answer that yes, that light is supposed to be on.

I think the only reason the flight didn't cancel was because the next day was Thanksgiving and the crew wanted to be back in PHX.