According to this article, the dead were buried there by Palestinians, the mass grave was checked by IDF for hostages' remains, then re-buried, it claims that IDF does not tend to Palestinian remains in Gaza:

The Israel Defense Forces on Tuesday rejected Hamas’s allegation as “baseless.”

It said forces searching for Israeli hostages had examined bodies previously buried by Palestinians near Nasser Hospital and had returned the bodies to where they were buried after they were examined.

It has been documented that Palestinians buried their dead at the hospital grounds both before and while Israeli troops operated in the area.

The location of that burial site was geo-located by experts to the same location where Hamas officials claimed to have discovered the new mass grave.

Generally, the IDF does not tend to the bodies of slain Palestinians in the Gaza Strip. ...

The United Nations rights office claimed that some of the bodies were “found with their hands tied and stripped of their clothes.”

The IDF, in its response, said that during its operation in the area of Nasser Hospital in recent months, troops examined corpses that had been buried by Palestinians on the medical center’s grounds, “as part of an effort to locate hostages.”

The military said it operated in a “targeted manner,” only where it had intelligence that Israeli hostages may have been buried.

Curious if there is anything to this or if it is just another false allegation.