Polyp extension theoughout the day

[FishOkay]

Is it normal for lps corals or any corals infact to extend and retract some of their polyps throughout the day not completely retract all their polyps but just not as fluffy at certain times of the day if that makes sense.
I find most of my corals seem to have certain periods of the day/lighting schedule where they look really good and all the polyps are out but then maybe 2 - 3 hours before lights out they don't seem look as good maybe.
On occasions its random aswell and for an hour or so the corals won't look as good as they normally do.
My initial thought is that maybe they are protecting themselves from the intense lighting for a period of time during the day or it could just be normal I'm not overly sure.

 

[davidcalgary29]

Completely normal. Leathers tend to sulk, shrivel up, and look like they're about to croak on one day, and then completely perk up the next. Many LPS species also feed much more actively at night, and will extend their sweeper tentacles alarmingly far, at which point you will realize just how big the polyp can get. Even cnidarians have their "personalities"...

Lighting damage tends to manifest itself in bleaching (or browning). Tissue retraction and necrosis can be caused by a host of other problems.

 

[Alexopora]

It really depends, are there any changes to the tank throughout the day? Like perhaps your waterflow changing according to schedule or lighting.