What surprising advice did Sai Baba give to Das Ganu when he came with a doubt about the Ishavasya Upanishad?

When Das Ganu arrived in Shirdi with a doubt that arose while writing his commentary on the Ishavasya Upanishad, he approached the Satguru for guidance. As recounted in Chapter 20, Sai Baba's response was quite unexpected. Instead of explaining the scripture himself, Baba told him, 'The resolution of this doubt of yours will be done by the maidservant at Kaka’s house When you return there.' This mysterious instruction set the stage for the subsequent events in the story.