I heard about an event where Sai Baba treated two visitors differently regarding dakshina. Can you provide details from the Satcharitra?

Yes, this event is detailed in Chapter 36. Two gentlemen from Goa came for Sai Baba's darshan. In a puzzling interaction, Sai specifically requested a dakshina of fifteen rupees from one of the men, which was given happily. The other gentleman, unprompted, tried to offer thirty-five rupees, but Sai Baba outright rejected his offering. This act of apparent partiality was perplexing to the onlookers. As the text in Chapter 36 highlights, this caused great surprise, prompting Madhavrao (Shama) to question Baba directly about the reason for his different treatment of the two devotees.