I once made the mistake of shouting "Landscape!" at my Wife when she was trying to take a picture of myself and my friends. Now whenever a picture is taken in my presence someone shouts" Landscape!" at me.
I wouldn't mind, but I was right and she was wrong, but I get ridiculed for it.
I just had this same issue - I found that if I opened the image in Photoshop (or similar, eg Photopea) and saved again without changes, a portrait photo works fine. Not sure why that would be though!