I dont know the exact reason. But maybe it has to due with the fact that a LY 747 was hit by a Tow at CDG this morning and that flight and plane instead of leaving today 4/13 will leave on Sun 4/15, due to having to be inspected and posssibly repaired and probably due to the Shabbath arrival if it did in fact depart today after everything was given the OK, it was passed on to Sun.

So maybe that plane was suppose to to come in from CDG and go out on 4/15 to JFK and return back on 4/16 to TLV. Or maybe it was suppose to be used for another Destination and instead they are using the Plane from the Flights you mentioned and thusly the flights you had in question will be delayed awaiting other Equipment that has to arrive.