Maybe your electrical system powering the lights was picking up some energy from the lightning. LEDs respond instantaneously to power changes while incandescent lights depend on heat which takes a little time to change. Also the much lower power used by LEDs would make them more responsive to small amounts of energy induced into the wiring from the lightning.
Just a guess.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory