#overinflated

I have had this mushroom for over a year I think it’s a Yuma. It has always had one kind of bigger little balloon (for lack of knowing the actual term). This morning I noticed that bigger balloon is huge and the rest are a little shriveled. What’s up with it? Looks healthy otherwise... is it...

So some of my corals, specially my new chalice coral, candy cane, and space invader pectinia look super inflated when the lights are off. They good during the day too but at night they seem to inflate even more, and this is contradictory to what I have seen on many threads about corals shrinking...