Eoria sings 'Her face was pale
Her eyes were blank,
Her lips were crimson red
A fading, floating phantom
From which her suitors fled!'
You flee from the Nightmare Life-In-Death!

This happened to me more than once, and its annoying that it can rid me of my stand, stop combat for moments, and make me flee while fighting other things. I would figure that with the extreme amount of concentration it takes for stand that you wouldn't run like this and cancel it.

CS keeps people from shoving/dragging/pushing you around to different locations... but it doesn't stop you from choosing to move. Nocturne essentially tricks your character into moving. (Equally, there might be ways for you to remove this as a possibility.)