The reference pitch DOESN'T define a complete equally tempered scale. It's perfectly possible to tune to A=440 and use any number of differently-tuned scales based on that.

Azizi will probably have encountered the problem with African music (since sub-Saharan Africa probably has a greater variety of scale patterns than any other region of the world). Highland pipes need to be accurately tuned with each other if they're going to play in a band, but their scale has never been complately fixed, there are several variants used for different traditions, and none of them use either equal temperament or just intonation.