I have a staff profile picture with the Crop behaviour set to Faces, on the website (editing the app) it’s displaying properly. But, on the phone, it’s displaying as if the option were Centre.
Face detection is hit or miss sometimes. Hard to say why it doesn’t work sometimes. If I were to guess in this case, it may be having trouble with face centering in both the editor and the published app, but the screen dimensions are different in each case, so the screen dimensions on the editor makes it appear to be working when it may not be.
I would try a few different images to see if it’s only this one image, or if you have the same issue occurs with multiple images.
I personally never managed to get it working…