The Satcharita mentions Sai Baba left his body, so how can it also claim he didn't really die? What is the philosophical explanation for this?

According to the teachings in Chapter 43, the concepts of birth and death are tied to the physical body and senses. For an ordinary being, birth is the union of body and senses, and death is their separation. However, for a perfected being like Sai Baba, who is described as the complete Supreme Brahman, these are considered false imaginations. The text explains that death for saints is like a solar eclipse; it appears to be a total event, but it is merely a defect of our vision, not a change in the sun itself. Sai Samarth is described as a 'mass of bliss' for whom birth and death are not applicable because he is devoid of bodily impulses. He consciously chose to merge back into his unmanifest form, a process described as burning the body in the fire of Yoga, making his 'death' a voluntary transition rather than a cessation of being.