Can you elaborate on the problem Das Ganu faced while writing his commentary on the Ishavasya Upanishad and Sai Baba's unusual advice from Chapter 20?

As detailed in Chapter 20, Das Ganu was composing a commentary in simple Marathi called the "Ishavasya-Bhavartha-Bodhini." While he managed a word-for-word translation, he struggled to grasp the deep, internal secret of the Upanishad, which left him unsatisfied. When a specific doubt arose, he traveled to Shirdi to seek guidance from his Satguru, Sai Baba. Instead of providing a direct explanation, Baba mysteriously told him, "The resolution of this doubt of yours will be done by the maidservant at Kaka’s house when you return there."