Many flights in Dubai happen late at night / very early morning due to a combination of time zone alignment and daytime heat making it harder to service large planes.
It could be fueling issues. I once had a Summer flight which was suppose to be direct from Athens to NYC that had to make a pitstop at Heathrow for fuel. It was so hot in Greece they couldn't fit enough fuel on board to jump the pond without a top off.
I've never heard of that before, and I've taken flights out of Israel in 43°C weather. Could just be a 'fuel price' thing