Why was Dev so doubtful and disappointed after his Udyapan feast, leading him to write a letter to Jog?

Dev felt doubtful and disappointed because he believed Sai Baba had not kept His promise to attend the Udyapan feast. As described in Chapter 40, a Sanyasi with two companions did attend and eat, but a "veil of Maya" prevented Dev from recognizing him as Baba. Dev's mind was fixed on the idea that the Sanyasi was just an ordinary guest. This led him to feel that his loving invitation had been met with a broken promise. In his distress, he wrote a letter to Jog, expressing his confusion and disappointment, stating, "I waited with great effort, but no experience came... I don't understand this at all."