Do plate corals spawn?

[carverbeezkneez]

I was just wondering if plate corals spawned? I was just turned the pump off and was about to feed, when I noticed the orange plate coral pump out a whisky milky puff. I have seen the plate "poop" and it was definitely not that. My wife saw it a few seconds later as it was dispersing. It only happened once, I fed the tank a few minutes later, and it ate like normal.

I recently got a blue plate and it did fine for a few weeks and then the other day started rapidly receding. I moved the blue plate into quarantine today and the orange orange plate "spawned" about an hour after I moved the blue one out. The orange one is really healthy and they were both right next to each other. Water params are fine as well.

Thanks ahead of time.
Andrew