In the case of M17, where a royal was buried, perhaps Huni or a son of Huni or Snefru, the tomb was looted but the skeleton was still in the sarcophagus - so no motive of reburial here.

Some remains of a body were found in Snefru's northern pyramid but these are open to interpretation - whose remains were they - an intrusive burial?


As for other OK pyramids:

Neferefre, Abusir, pieces of pink granite sarcophagus, fragments of four alabaster canopic jars, fragments of a mummified body probably belonging to a man about 20 - 23 years old when he died.


Teti, Saqqara, blackened remains of a mummified arm and shoulder in the burial chamber.


Pepi I, Saqqara, a stone sarcophagus (probably a substitute) - a fragment of a mummified body, a left wooden (reddish sycamore?) sandal, a piece of linen with the inscription "Linen for the king of Upper and Lower Egypt, may he live forever", a piece of pleated linen,14 shards of the canopic vessels (yellowish alabaster), and a small flint knife.


Merenre, Saqqara, mummified body of a young man - the type of mummy wrappings are consistent with 18th dyn custom, but a few Egyptologists think the mummy may be Merenre.


An inscription in the 'antechamber' of the pyramid of Unis, has Horus conducting the ka (kA) of Unis to his body at the 'Big Enclosure' (Hwt-aAt) which was in Iunu. Perhaps this was a part of the funerary rituals before the body of the dead king was placed in his pyramid, but could it be possible that the king's body was actually buried at the 'Big Enclosure', and the pyramid was for the ka of the king? The ka rejoined the body at Iunu and from this eastern horizon the king was reborn?


A Dyn 6 Pyramid Text mentions Akhs and gods crossing over for their meals each morning and evening to Iunu. note: Akhs (Axi) were the deceased, "whose ba has reunited with its ka, making possible eternal life as a spirit among the living."

CT