Anemones will move wherever they want to in order to find the perfect place for themselves. It could've moved because it had too much light, too much flow, too hot, or even the opposite, too little little, too little flow, and too cold.
I don't think bubbletips hide at night, so he probably went on a road trip to find a better place to sit. When you get your new lights up he'll probably move again. I wouldn't worry about it too much unless he decides to wedge himself inbetween some rocks and you can't see/get at him to feed him.