It depends greatly on your device. On my work windows machine I can see a bit of banding. On my phone, it's worse. On my macbook, it's atrocious.

Like most folks you were probably simply looking at the foreground. The background around the edges of the shirt and the edges of the picture (depending on the image) noticeably change color from shot to shot without full screening it on my small Android 12 device.

It's artifacts made in the background of the image that this poster is complaining about.

My sight's both poor and uneducated, but looking again after the defects are pointed out, they're pretty stark.

Good for you. Once you noticed the banding issue, you're cursed to see it everywhere.

very interesting, i could clearly see the difference - even before reading. and i'm using a 9-year-old MacBook Air 11'... not bad, but not exactly high-end stuff.

fascinating how perception is different.

Your viewing environment will matter a lot. In a dark room with a bright monitor, the banding in the background of the example images is pretty bad (if you are looking for it). But if you have a laptop in a bright sunny room in front of a window causing back lighting, you probably won't be able to see it.

It's there. It's very noticeable once pointed out. It drastically distorts the images' 'softness' because of the harsh steps through the gradients. It does not appear as the artist intended for it to, which is the biggest issue.