What was Dev's specific reasoning for not recognizing that the Sanyasi was Baba in disguise?

Dev's failure to recognize Baba was due to a specific sequence of events that he believed caused his delusion. As Dev reflected in Chapter 40, the Sanyasi had first appeared at his home for a different purpose—collecting funds for cow protection—and this happened before Dev had even sent the Udyapan invitation to Baba. Because this initial meeting was for a separate, worldly reason, when the same Sanyasi returned asking for a meal, it didn't occur to Dev that this could be Baba fulfilling His promise. Dev lamented that if the Sanyasi's first visit had occurred after the invitation was sent, his "vision would not have been so confused."