I didn’t say they were features.
If you want a HA which switches automatically you need to get Phonaks, which have “Autosense”.
I prefer manual program selection, because I know when I need to use specific programs. I tried Phonaks a few years ago, and found auto changing to be problematic.
The general program’s main function is to help you understand speech, so frequencies within the range of speech are amplified, whereas a music program will be more linear.
The flanging effect is, as I said before, due to the feedback management, which your fitter should adjust.