They can inflate quite heavily for no reason on occasion. Not usually something to be overly concerned about unless it is one of the corals showing receded areas. I would definately look into the cause with those corals.
I don't see a pic though
Unless it's the Jan 15 in your gallery section?
In regards to lighting, it will inflate a little more if it's not getting proper intensity. PC
's will usually need changing around the 9-11 month mark depending on hours/day in use. I also finf they will inflate a bit more if alkalinity is off (low usually).
, Wellsophyllia is not a true genus, it's properly refered to as Trachyphyllia radiata
. Without a better pic, I'd say yours is a geoffroyi
. What does the base look like?