Alhambra Sliding Door - crinkling noise

[Hinksy]

Hello. I was looking at Alhambras in two car dealers yesterday and both the cars made a crinkling sound when I opened one of the rear sliding doors, in fact, one car did it on both. It almost sounded like a crisp packet or plastic was caught in the mechanism. Has anyone encountered this and have any idea what it is or how to resolve it? Should I be concerned?

Thanks!