Just looked back at the period in question, it was showing about 599,000 feet and then there were some data blips, then they switched target lock to Madrid, and we got to see the altitude data decreasing a bit and then another switch of data target and then something from mission control that sounded like 'newton 4 shutdown initiated'. At which point the commentator said this was the shutdown of the second stage engine, and claimed this was the completion of the first burn of the second stage. However I'm not sure that was the correct interpretation, and all signs were increasingly bad from that point onwards, altitude fell several hundred thousand feet further before data stopped and the commentator started diverting attention elsewhere, never having acknowledged the altitude drop. Lack of meaningful updates after that point further raised suspicions of failure, but they didnt have a glossy corporate script to deal with this eventuality.