Astrea Snail Suicide

[DiverDude]

Put a couple of Astrea snails in my tank and within 48 hours I found one upside down in the rocks.

It would appear that it fell and landed upside down, wedged in the rocks. It could have been this way for up to 10 hours before I noticed. I picked it up and put him (her ?) right-side-up on a rock expecting that once it sensed that the world had righted itself that it'd pop back out, but it hadn't 24 hours later.

Is this a freak accident or is this common ?

Seems to me that snails have a pretty good grip so maybe it wasn't an accident at all....maybe the hermit crab is looking at hard time ?