The pair of Van Ness I owned a few years back had something similar looking on the inside. For curiosity's sake I lifted and peeled it back a little- It was a thin layer of leather, with what seemed like a thin layer of cotton-like material underneath (imagine a cotton ball). No idea what was underneath that layer though... I didn't peel back too much because the insole was not removable.
I can't speak to what that cotton-like material was, or if the new strands have the same insole, but it did have the same appearance. It did make the shoe seem less "deep", so I can definitely understand when others say it changes the fit of the shoe.