I haven't found one, like I mention in the article; I'll edit it if someone proves me wrong.
I'm starting to get a feel for a pattern - the books tend to be more expensive, and also take longer on average to deliver (a few weeks, instead of a few days). The latter would be normal for rare editions and some third-party sellers, but if I'm ordering a popular book and it takes longer than usual to deliver I can kinda smell the dead rat. But the only way to know for sure is to open the box in disappointment.
I've ordered books that were print-on-demand and had them arrive in 3 days. Some of the Amazon ones will have the exact date in the back, and I can see they were printed the day I ordered it.
For what it's worth, I think print-on-demand is a win overall, while there are lots of low quality stuff out there, the ability of small authors to get published and readers to find rarer stuff out weighs that.
I can't necessarily speak for that specific book, but a youtuber I follow (who has POD books as one of her particular bugbears) has stopped recommending bookshop.org after personally getting POD copies from there.