The AAIB's short recent report is clear that the right engine stopped first, although it doesn't explain the evidence for that. That's in the expected order from the sizes of the supply tanks.
The amber and red fuel warnings come from different sensor system, and so any crud living on the sensors shouldn't affect them both. A red warning should appear with at least ten minutes of possible flight, and 30kg of fuel in the supply tank, remaining.
I understand that the amber fuel warning appears whenever the supply tanks go below full. Depending on orientation and acceleration, I can imagine that happening at different times for the tanks 1 and 2 despite their slightly different capacities.
There are already questions about the status of display and perception of warnings, from a display fault, from any issues related to the bulletin about the sensors, and as mentioned just today, perhaps from issues of ergonomics with goggles.
There's some commentary from the manufacturer at
FAQ - Airbus Helicopters
All, as a non-helicopter professional, please feel free to PM/post if I am providing noise rather than signal or wearing out my welcome. I've been following the thread and events closely, and am intrigued by this strange investigation, but appreciate that I am a guest filling your inboxes.