Not quite sure what's going in here, but I've had explosive growth lately coming off this sps piece. It's not coloring in, it's white-ish, but has feelers and shows all signs of being healthy. Is this a retard coral, or what?
I can't really tell from the picture the spacing between corals, but could it possibly be that it's growing in that pattern because of stinging venus fly trap-like palys behind it?
So I had something similar on mine on one of my milles. I just assumed it was a coral tumor. it grew so fast it didn't even have time to grow polyps...
After the quick explosive growth, it completely stopped, but was still alive.
Here is a picture of it now. Look in the center of the picture, you will see one branch that looks smooth. It is coloring up now after about 3 months since the growth, and the rest of the coral finally caught up.