Why did Dev feel that Sai Baba had deceived him regarding the Udyapan feast?

Dev felt deceived because his expectations were not met in the way he anticipated. According to Chapter 40, after lovingly inviting Sai Baba to his Udyapan ceremony, Dev waited with great anticipation. However, Baba did not arrive in his known physical form. Instead, an unknown Sanyasi and two companions, who were uninvited, came and ate. Dev served them but remained oblivious to their true identities. This led to his disappointment, as he wrote in a letter to Jog, 'I waited with great effort, but no experience came...it all turned out otherwise; I don't understand this at all.' His feeling of being let down stemmed from his inability to see through the 'veil of Maya' and recognize Baba in the Sanyasi's guise.