I don't think I can blame this one on "driver error" as some others have suggested in the past.
I'm into the second sector of the final lap with still 4.x fuel left (on a 3.8L 5/5 track) and my driver tries to pit. It was a wet race that turned dry, but you can see I have "follow wet weather" strat unticked, so I can't blame that either. I'm not exactly tight on fuel, in fact I still had 1.2L after I crossed the finish line according to my data.