These seem to be majano anemones. They are usually considered a nuisance and should be removed or otherwise destroyed. The problem is that they often reproduce to the point where you have a massive ammount of them, and they can sting the corals you want to keep.
It's possible, you might be able to see more directly that I can in a photo. I would say that it's much more likely to be a majano anemone, because these are a well known pest anemone in reef systems.