Snail shell falling off

[joshfriend09]

Its king of hard to see in the pic, but it looks like the shell is falling off of my snail. Is this normal? Shortly after taking the picture, the snail somehow pulled the shell back on. Not sure if this could be an identifier of an underlying issue or something?

 

[SlugSnorter]

its a shell, its heavy and their body can stretch out of little more at some points when they are moving vertically like that