Presumably there is an image store with all the profile images stored which is also used by MS to store the default image and populate the emails?
Plus some weird naming of the default image?
Or finger trouble with an update which pointed to the user area instead of the system area?
I think efforts should be made to get enough information for a "who me?" story. This does have the feel of a naming policy which was vulnerable to a minor configuration slip.
Alternatively the developer used their own chosen image file from their personal profile by mistake?
Edit: if someone could disassemble the App (since this seems to be cured by updating the App) it might be instructive to see the path name used.