Looks like Apple is aggressive in pushing their RAW files from the iPhone before writing them to dng.
I'm attaching the original image (with everything in Adobe ACR zeroed out) taken with the iPhone 12 Pro, together with 200% and 400% crops. The halos are ugly.
This was taken with Apple's default Camera app. I wonder if there's a difference with some of the other apps like Halide, ProCamera, Manual, etc.