I've kept many LTA's (M. Doreensis)over the years, they all have kind of closed up, some very tight like a baseball, I even had one pull into the sand for almost a week just because a snail fell on it, thought it was a gonner and then it just popped back out.
LTA's are kinda sensitive to light, shadows, vibrations or touching them, and since light is their main source of energy they may pull in when lights go down, especially in heavier flow areas it seems.
Too bad photobucket is being a bummer, I have some good shots of this saved there.