I think with Paphs (in my experience) its just a matter of having your new roots adapt to the medium. They're so hairy and delicate they don't seem to like a change of medium, but if you stick with it the new roots will adapt. I use small coconut husk chips only. And i feel a lot happier about that choice after reading
this article.
After changing from bark in their compot to perlite and then to bark again and THEN to husk, the poor things didn't grow and i lost heaps to rot. But i stuck it out with the husk, put them in a more airy position and they're all growing new leaves and lovely, fat, hairy roots.