If you take a look at thebasource then you will see that BA had to fly a 777 to Bermuda a few times non etops due to a minor engine fault. It took about 1.5 hours longer. Not sure what etops is or if linked to this but as mentioned above I am sure planes fly with little niggles, but they won't fly if not 100% safe. Not worth it in any instance.
I would bet my house that there was no safety issue here - VS (and other top-class airlines) would never fly a plane if it were unsafe - I can guarantee that.
There are a great many faults that are allowable on a plane (very tightly regulated and approved by the manufacturer), that might limit operations but NOT safety.
Apart from anything else, a serious incident is the very worst thing that can happen to an airline (just look at what has happened to Malaysaan, and at least one of those was due to outside forces). If it were discovered (and it would be), that the airline had knowingly dispatched an aircraft with a fault not documented and approved, that would be it - license removed, airline collapses.
I am absolutely confident safety was not compremised in any way.
The curious part of me just wants to find out what the issue is!!!
ETOPS - Extended-range Twin-engine Operational Performance Standards, is an approved regime the governs the operations of planes with two engines only and is designed essentially to limit distance/time from suitable airports (which is why certain routings happen) in the massively unlikely event that one engine develops a fault (and, all twin engine planes can take-offf, fly and land on a single engine by design and by regulation).