maybe its just one of those weird plant things since it was a second generation cutting it may have adapted itself to growing in 10% rh,i have a hell of a time hardening off seedlings and clones to survive out from under the dome...
unc get some clear plastic cups and set it over the top of the freshly rooted cut, off set it a little so air can get in, usally after 24 hrs i can take the cup off with no wilting,