I'm not sure if the lights are having that effect on the bubble coral. At this point the bulb isn't 'new' to the tank anymore. Everything in the tank should have gotten used to it by now. I have a doughnut coral (going on two years) and twice since I've had it it has closed up completely for a couple months at a time. First time round I thought it was dead but kept it in the tank cause there was still tissue on the skeleton. When it did open up again it was bigger and better than before. Take a look after lights out and see if it has its feeding tentacles out. I think all you can do is keep a close eye on it. Hopefully it's like my doughnut coral and will come back for ya.
Not sure if this helps but it's my 2 cents
