Arrab
A reasonable question. The crucial point arrives when a pilot intentionally continues flight in the knowledge that the aircraft will land with below minimum fuel reserves.
You kind of need a good excuse for that.
Faulty fuel guages could be considered a valid reason, or it may be that the flight must continue for safety reasons to avoid hostile terrain, weather, etc.
In this case, SilsoeSid has posted some very informative pictures that suggest that the pilot was perhaps flying with no fuel information due to a display fault.
It wasn't lack of fuel that was the problem, it just wasn't getting through to the engines. There was sufficient fuel overall to continue flight to the destination and land safely despite the fact that fuel minimums would have been breached. It was reasonable to continue the flight to base given the circumstances.