I think Dizzy had changed the tile already in 1946. He recorded for Victor under the new title in February of 1946. I found a picture of an old 78 issue that lists the tune as "Night in Tunisia (Interlude)" so it changed pretty early. I know that Sarah Vaughan recorded it for Continental with Billy Eckstine as "Interlude" in 1945, so my guess would be that the title change came late that year. Tristano may not have heard it under the new title when he recorded it for Keystone as "Interlude" in October of '46.