Airbus FBW - triple clicks

[AirbusFan]

Just seeking clarifcation of reasons for the triple click 'alert' to sound. My understanding is that it occurs on a downgrade from say cat 3 to cat 1. Some other text says that it also occurs when a new altitude is selected during ALT* and the ALT knob is not pushed or pulled.

Are these statements correct and are there any other causes?

Thanks in advance

AirbusFan.