Iphone 13 pro half circle lines in middle of photo

Why am I getting these half-circle lines in the middle of my photos in bright sunlight? Is it a reflection of the lens? I believe it only happens in portrait mode. It's a different issue from the known lens reflection dots that appear in pictures. As you can see below, there are clearly defined lower circle half lines across my photos. Anything I can do to avoid this? Please let me know - thank you!