i can also confirm this issue

in my current playthrough, doing exactly the same thing as i've done on previous runs (accept reward for saving her, close dialogue, reopen dialogue to get on the ropes quest), she instead tells me i have nothing to offer her without even mentioning gwydian. it seems that if you accept the reward for saving her it locks you out of interacting with her for the on the ropes quest. kind of annoying and probably a bug, but not something that bothers me especially since i never accept her help for mastering source anyway