Not sure if this is a bug but the Azerite Essence Media is returning an id different from the one used on the url param which is the same as the one listed on the media object from the Azerite Essence endpoint.
https://us.api.blizzard.com/data/wow/media/azerite-essence/2?namespace=static-us
Requesting the azerite media 2 is returning a media object of id 293019.
{
"_links": {
"self": {
"href": "https://us.api.blizzard.com/data/wow/med..."
}
},
"assets": [
{
"key": "icon",
"value": "https://render-us.worldofwarcraft.com/i..."
}
],
"id": 293019
}
It appears the Azerite Essence Media endpoint is returning the same id as the main_power_spell present in the first Azerite Power.