Bob,
I looked at your pictures and I'm not sure what is going on there, it could be budding off, but that isn't really described for that species. You do have Manicina areolata by the way
Just because it isn't described doesn't mean it doesn't happen, so it could be budding, but it could also be simply an infection or some kind of air pocket or tumor. It could simply be swelling.
Have noticed any small brains on the rocks nearby after one of the swellings goes away?
Brian