The most prominent thinker of the Advaita Vedanta school is Adi Shankaracharaya, but he wasn't the founder of Advaita; Adi Shankaracharaya's guru Govinda and Govinda's guru Gaudapada were also Advaitins. As I discuss in this question, Gaudapada is famous for his commentary on the Mandukya Upanishad. But I'm interested in Gaudapada himself.
As you can see here, according to Advaitin tradition Gaudapada was the student of the sage Shuka, son of the sage Vyasa, and then the Advaita Sampradaya is traced back through Shuka's ancestors: Vyasa, Parashara, Shakti, Vashishta, Brahma, and ultimately Vishnu. My question is, what is the story of how Gaudapada met the sage Shuka?
I've found one possible story which is from a seventeenth-century work called the Patanjali Charitam. In this account Gaudapada starts out as a student of Patanjali, the ancient grammarian and author of the Yoga Sutras. But Gaudapada displeases Patanjali, who curses him to turn into a Brahmarakshasa or cannibalistic demon. The only way for Gaudapada to be free from the curse is for someone to correctly answer a Sanskrit grammar question. After many years of roaming the forest as a Brahmrakshasa, Gaudapada finally comes across Govinda, a boy who correctly answers the question. Gaudapada then proceeds to teach the boy all about Sanskrit grammar, and this finally frees Gaudapada from the curse. After he returns to his human form, Gaudapada goes to Badarikashrama, where he meets the sage Shuka and becomes his disciple. Then years later, Govinda goes to Badarikashrama and finds out that Gaudapada is now an Advaita Acharya, so he decides to become his disciple (taken from this forum post):
After Gaudapada taught the boy, he was released from the curse. He then went northward searching for a guru. Having heard that Sukadeva was identified with the entire universe, he felt a desire to become his sishya and learn from him. After a long search he met Suka at Badari and was initiated by him into Advaita Darshana....
After searching in various places, [Govinda] finally went to Badari and met his old guru who had taught him grammar. He learnt that Gaudapada had become a sannyasi. He too took sannyasa from him. From then on, he was called Govinda Bhagavadpada.
So are there any older works that confirm the story given in the Patanjali Charitam? Are there any alternate accounts of how Gaudapada and Shuka met? I'd like to try to find the oldest known story of their meeting.