I adore my girl SZA and after listening to The Weekend just now I maintain homegirl is a full on genius. THAT SAID. She said her voice was gone but sis... vocal tiredness don't create pitch problems like that...
like sure you might be a little under the pitch bc you're straining but the good sis was losing the plot (and the key...) on riffs more than once. It's OK because again she is a GENIUS and I would 1000% go to a SZA concert tomorrow, but... just to be clear, that excuse don't fly.