When I change the aspect ratio from 4:3 to 16:9 and I take a photo, iOS 16.4 will save two images in the mobile storage, one for 4:3 and another one for 16:9. I could visualize this "normal behavior" using Windows 10 from File Explorer.
Is it happens to do the same to you ?
You can only see the duplicates accessing a file viewer; using iTunes or Gallery in iOS will show you as it as one photo taken, but in the storage there is for two! One is called
IMG_[number] and the other one as it was edited
If you keep 4:3 then only one photo is taken, so I presume this is the default image that is editing after.