Xeque
Read the report, it clearly explains that the engine control units did exactly what they are designed to do, correctly detecting and reacting to the events of the last 720ft of the descent.
It also clearly states that this incident is unique in 6.5 million flight hours, so your assertion that it would have surfaced before doesn't fit with the observed instances of the event.
Fascinating report, and clearly some more tests that exactly recreate a 777/Trent 800 installation will be needed to accurately pin down the details of what and why as the tests that have been done show some differences from the recorded parameters on BA038.