Now that's interesting-747 incident

[punkalouver]

Occurrence Summary :

A12W0087: While en route from Anchorage, AK to Covington, KY, the crew of Atlas Air flight GTI8904, a Boeing 747-47UF, declared an emergency due to low oil quantity indications on 3 engines (GE CF6-80). The flight was diverted to Edmonton Intl (CYEG) where it landed at 0947 with ARFF on standby.

[patrickal]

Sounds sort of like this incident from many years ago:

On May 5, 1983, Eastern Air Lines Flight 855, a L-1011 registration N334EA, while flying from Miami to Nassau, shut down the #2 engine due to low oil pressure and began a return to Miami. Both of the remaining engines later failed. Without power, flight 855 descended from 13,000 to 4,000 feet (1,200 m) before the #2 engine was restarted and the aircraft landed in Miami without injuries. Incorrect engine maintenance had led to the loss of oil on all three engines.[65]

If I remember correctly, there was an O ring left off each of the filler plugs on each of the engines....or something like that.

[12 twists per inch]

O ring seal on the mag chips if I remember correctly - been replaced under routine maint, seals not fitted. Now subject to independant checks prior to fit.

[Mr @ Spotty M]

CF6-80 series engine have a tendency to hide oil, so it is not unusual to see oil indications reducing from 20 to around 8 in flight.
Maybe that is what they had and not a leak.