This is the classic Airbus trap that has historically not been understood nor trained to understanding on conversion courses etc. The Airbus autothrust needs logically to be in 'speed' mode when flying a visual approach. This is achieved by turning both flight directors off. The A380 automation has recognised this potential trap by incorporating only 1 f/d. I am disappointed that after 25 years of airbus fbw operation this is still not properly understood. If I am going to apportion 'blame' I would cite training departments.