What was the specific context and actions that led to the argument between Anna and Mavshibai?

The incident described in Chapter 24 occurred while several devotees were performing service for Sai Baba. Anna, who was over fifty, was pressing Baba's left hand. Mavshibai, also of mature age, was massaging Baba's stomach with great vigor, twisting and churning as if "grinding" buttermilk. In her absorption in Sai's name, she swayed back and forth, and her face came very close to Anna's. Seizing the opportunity for a joke, Mavshibai accused Anna of trying to kiss her, saying "Have you no shame for your gray hair?", which sparked the quarrel when Anna reacted with anger.