The US peace proposal says the status quo at Jerusalem’s Temple Mount should be maintained, but also that all faiths should be able to pray there — which is a change from the status quo.
The plan says “the status quo at the Temple Mount/Haram al-Sharif should
continue uninterrupted.” It goes on to say “Jerusalem’s holy sites should remain open and available for peaceful worshippers and tourists of all faiths. People of every faith should be permitted to pray on the Temple Mount/Haram al-Sharif, in a manner that is fully respectful to their religion.”
Jews and Christians can today visit the Temple Mount, but only Muslims are allowed to pray there.
The discrepancy can perhaps be traced to a statement in regards to the status quo that “all of Jerusalem’s holy sites should be subject to the same governance regimes that exist today.” Keeping the status quo may then refer only to governance of the sites.