Branching Frogspawn question

[mark]

Had this coral for more than a year and when was having new branches before they would just seem to appear. Last few branches there's been a large bubble forming first, ideas why?
http://i67.photobucket.com/albums/h316/das75/FS.jpg

[psychedelic]

My frogspawn went through the same thing...but usually when it was stressed. I did a water change and the big bubble went away for me.

[surgeonfish]

Is there any other corals close to the frogspawn? My frogspawn did the same thing when some polyps fell down near it. The bubble was the start of a few long sweeper tentacles.

[Der_Iron_Chef]

I've seen people explain that it's a spawning behaviour, too. Not sure myself, though, as I've never experienced it.