This is just a thought here and may or may not have anything to do with it as I cannot handle the fabric to feel what it like but I have actually made my own batik fabrics in the past from 100% cottons. What I found was that with all the resist work (using wax for this) and all the various dye baths and mordants, the fabric seemed to become more stiffer as each colour of dye was added. Even after all the wax was boiled out the fabric was no longer soft like the original plain white cotton, so I am wondering if it is perhaps just that kind of process?
Gal