I just got my new iPhone 15 and I have noticed that while taking I just got my new iPhone 15 and I have noticed that while taking photos under the bright lights of my garage, landscape 16:9 photos under the bright lights of my garage, this artifact black bars appear on the photos. If I turn the lights off, it stops! Apple Support said they have a record of several people reporting this issue and they have the engineers working the problem.
This issue keeps cropping up on me too. In fact, I have decided against purchasing an iPhone 15 for my girlfriend for Christmas. Her 12 mini is more reliable.
I did discover that if you switch to RAW the bars go away.