Agreed, this is not back EMF.
Perhaps the problem is the LED lamps do not have sufficient inrush limiting, and while the current isn't enough to trip a breaker, it applies excess wear to the switch as the switch bounces at turn on.
Still, this was probably more a switch at the end of life, than directly related to the LED install, I can't see even the most optimistic assumption about inrush burning a switch out in a few weeks.