The Deccan has more shrines visited by people of more than one religion than almost any comparable area, and interpreting them is harder than it looks.
The pattern is well attested. Sufi tombs across the plateau receive Hindu visitors who make the same offerings and ask for the same things as Muslim ones; some Hindu shrines receive Muslim visitors; a number of sites have parallel or joint arrangements for both. Practices such as tying threads, offering cloth, and seeking cures for illness or infertility cross the line freely, and in many places the families who serve at a shrine have done so for generations without regard to the wider category.
Two readings compete. One treats this as evidence of a genuinely shared religious culture in which the boundary between Hinduism and Islam was porous at the level of practice, whatever the theologians said. The other, argued by Peter van der Veer and others, warns that the sharing is often shallower than it looks, that it coexisted with clear communal boundaries in other domains, and that the modern political uses of the evidence, in both directions, distort what is being described.
What is not in doubt is that reformist currents in both traditions have attacked the practice for two centuries, and that shrines have been flashpoints during communal violence. Shared use is fragile and has been broken repeatedly, which is part of the record rather than an exception to it.