It's called post-processing, I don't remember if Apple gave it a fancy name. I believe they did, but I don't remember it. Smart processing? Smart HDR? Something?
Likely a HDR effect? Check you have View Full HDR enabled in Settings, Photos maybe? Equally, could it be that the preview shown in Camera has all the auto-corrections applied already given the faster processor etc so there is no auto-correction to suddenly see on saving?