Question about Duncan coral, possible infection?

[Bananarama]

Hello all,
I have a Duncan coral, he has been in my tank for a few months now. I have noticed that when he has been expanding, there is a small section that he is keeping covered with his tentacles. I turned off the flow so I could get a good view (I've posted some pics). There is a small part which was being covered that looks damaged. The only think I can think of as being a cause is about a week ago (around the time I started noticing this behavior) I tried feeding him zooplankton. He got a mouth full, but started spitting it up right away. A few hours later I noticed what looked like a little pile of the zooplankton sitting on the spot that now looks damaged. I dont think there was enough flow on him to blow it away, so I took my turkey baster and tried to get it off. He retracted and that was that.

My question: Does this look like an infection that could have been caused by ( among other things) the zooplankton sitting and rotting on his disc, or does it look more like a bruise (potentially caused by my Peppermint shrimp trying to get some dinner). Or is it totally normal for a Duncan to develop little discolorations like this?

My Duncan is my favorite coral (hence the *he* pronoun instead of *it* haha) so I would be sad to see anything happen to him. Plus, he has been growing a lot of little heads so he is doing well otherwise.

My params are good, I have a mixed reef (mushroom/softy/LPS) with everything prospering.

Please let me know if there is anything I should do!

[AlSimmons]

It looks fine to me.. Before you do anything drastic you might want to give another week or so and see what happens.

[Bananarama]

Thanks for the reassurance! I will leave it unless it takes a turn for the worse.