Yep, normal enough. Not all of them will begin to get the inflated vessicles but, as mcgyvr said, once they do this and the progeny show the same tendencies then you could give it the illustrious "bounce" title. It has become generally accepted that the reason for the inflation of the vessicles is how intense our artificial lighting has become and a great many number of mushrooms and even other corals, like oshanickreef said in regards to his favia and blastos. Hope this was helpful and at any rate those are some very pretty rhodactis mushrooms you've got there.