True it could have been AUX starvation.
It is for this reason that the company I fly with currently that we change to inboards at Top Of Descent and plan the fuel burn from the outboards as the number of minutes prior to TOD. If it was fuel starvation then there is simply no excuse.
Leaving 20lts in the AUXs is a standrad practise by a lot of operators I have seen but still there is no excuse in running them dry. Someones head should roll.
Ang