Vlad There are still some results without the lens that are not receiving the PDF flag. I was hasty by giving the PDF lens point. Try this one without any lens:
https://kagi.com/search?q=sciencedirect.com++%E2%80%BA+science+%E2%80%BA+article+%E2%80%BA+pii+%E2%80%BA+S0004370209001398 (third URL, international, US-EAST)
But checking with Google, which tries to be somehow smarter in those detections, they have worse wrong matches. For example:
The same query on Google gave the PDF flag to https://www.sciencedirect.com/science/article/am/pii/S0959652619318141, even though there wasn't any embedded PDF at all.
