The only maintenance action that was reported (tech log) after this was, water draining procedure, without mentioning if good amount of water was drained out or not. The outer tank pumps have valves which delays the fuel extraction until inner n center tank are empty. But, precisely the scenario I was talking about Is that both outer tanks were made to provide fuel to the engines by manual feed. The left tank ended up with an intermittent depletion and so the fuel remaining on the left tank was 1000 kgs more then the right outer, they are supposed to be depleting at the same rate. There was no local or ecam fault alert either.