Bubbles on a Birdsnest

[BoomerD]

One of the members of the local reef club has posted this pic on our local reef site:

with the following information:
"I havent really been paying attention to my tank the last few months due to school, so I am not sure how long this has been happening. I just looked again, now that the lights have been out for about 20 minutes, and the bubbles are gone. I will try to get a better pic tomorrow, the lights were shutting off when I got this image."

Any idea what's going on here?

 

[Gibeon]

Are they where polyps should be? Polyp bail-out?

 

[SueT]

Thats kind of weird looking to me. It almost looks like the tissue has the bubbles under it. I was expecting to see algae bubbles on the tips which is very common, but not this.

 

[sasquatch]

Looks almost like something has been deposited there for hatching, hope its not a nasty.Steve