Avoid all light leaks into your grow area. I had, what I thought to be minor, light leaks during my last grow and wound up with some 'nanners' in some of my buds. This grow, I installed a 'blackout' curtain to block out that leak at the door to the room. So far (middle of 5th week bloom) I have not seen any problems, yet.
I have not seen any information on how or if a full moon affects the plants cycle, or if lighting flashes would affect them.
I will know in about five or six weeks if the light curtain made any difference.