What was the specific problem Das Ganu faced while writing about the Ishavasya Upanishad, and how did Baba say it would be solved?

Chapter 20 explains that Das Ganu was writing a commentary in simple Prakrit language called the "Ishavasya-Bhavartha-Bodhini" to make the scripture accessible to those who didn't know Sanskrit. His problem was that although he translated the Upanishad word for word, he couldn't grasp its "internal secret" or deep meaning, which left his mind without joy. When he brought this doubt to Sai Baba in Shirdi, Baba told him something quite unusual. As noted in the chapter, Baba's words were: "The resolution of this doubt of yours will be done by the maidservant at Kaka’s house When you return there."