Vandersteen 2ce Sigs with bass coupler issue

Just got lucky (maybe?!) and picked up a really nice used pair of 2ce sigs for next to nothing.  Everything sounds fine except one of them has a high pitched chirping/grating sound that gets worse as the volume increases.  I will be opening them up asap to take a look.  Just wondering if anyone else has had this issue?  I reached out to Vandersteen already and they replied quickly which was great.  Unfortunately, they couldn't add much except to say send it in.  

Would a voice coil rubbing cause a sound like this?  I'm thinking maybe the surround came loose and the cone is out of alignment.  Just a guess.

Thanks