Maybe someone else might find this interesting to see.
After opening the app that day, my swablu got raided by the Thundurus, appearing each time I opened the buddy tab, interacting with the swablu.
In the meantime, on the map it was showing a shiny Ampharos (I do not own one) After changing the buddy, the Thundurus got swapped to the Ampharos and it got removed from the map and only showed up on the buddy screen
by HaxerOne