Someone posted a similar situation with another Euphyllia, not too long ago. (it was a hammer)
Someone else identified it as "polyp bail-out", which is another form of reproduction. If you can, try to keep the polyps from blowing under rocks and dying. Other than that, keep an eye to see if they take hold of the substrate. My hammer coral has done it many times, but all the polyps blew away.
Mitch
[ January 09, 2002: Message edited by: Carpentersreef ]</p>