Not for the first time
QF has cultural form.
My dodgy memory has a 747 classic flying Bahrain-Heathrow long, long ago, and starving one engine of fuel at top Of Descent and a second (same side) on long finals.
Ultimate source deemed to be sea water in Bahrain fuel causing goo formation.
(What was the old joke as engines failed one by one - "At this rate we'll be up here forever")
Hopefully someone with more confidence in their memory will correct me if I'm wrong.