Strangest thing happened. I was experimenting with using my iPhone 12 Pro to shoot a cross country race. In the midst of shooting the iPhone using the Lightroom camera app, the app suddenly switched to produce a PNG screen shot rather than the Pro RAW photo I was seeking to shoot. Then the phone returned to a log-in mode which meant I scramble to restore shooting. I was actually pleasantly surprised by the quality of my edited shots in Lightroom, but will use my Nkon DSLR for future races. Please explain what happended to create this outcome.