To err is human especially if you don't believe your instruments.
Please excuse me if I use incorrect terminology. There are several ways to look at the situation. Here is one. First the pilots were presented with the high oil pressure and the low oil temperature. This must have caused some degree of confusion because they were never presented with this phenomenon in their training program. This may have introduced some concern that the computer was in error. Secondly, the A-330 fuel monitoring logic was such that the fuel level disparity was not provided to the pilots until a considerable amount of fuel was lost. Coupled to this the pilots were not monitoring the fuel pages that is until the disparity in level was indicated by the computer.
The pilot had in mind that there was a possible malfunction with the computer. The PNF ran several calculations indicating a substantial loss of fuel. Not knowing there was a leak the pilot opened the cross feed in accordance with the operating handbook. The pilot asked the flight attendant to check to see if there was a leak however it was dark and she could not verify that there was a leak. By this time it was too late. Although the pilot was confused (believing the computer was in error) all of his actions were in accordance with Airbus procedures.
Because of this Airbus changed the fuel monitoring logic and they prepared but never officially released an AD covering the actions to be taken in reference to several different leaks from different areas of the wing. This required visual verification by one of the crew. However if the leak occurred at night the leak could not be verified and the pilots were placed in the position of operating the cross feed at the wrong time placing the aircraft in jeopardy.
The basic cause of the problem can be traced to the engine manufacturer.