Sorry for the late reply. I am the poster who mentioned the searches for the crane and javelin accidents. When I did my testing, I looked at the meta-data on the page and found the false dates. So my impression is that google uses the page meta-data for their date, not the time that google actually found the page.
FYI you do advanced search.. choose a "last update" option. Then on the result page you can choose the "past X" drop-down and select custom range.
When I did that for the javelin impale story, which apparently happened may 9, I see page source like this. var DDO = { contentData: { .... contentPublishDate: "20190508225202", contentUpdatedDate: "20190509002942", ...
So my theory is that google is using the contentPublishDate, which various publishes are too stupid to realize they are fucking it up.