DOIs in student paper go to completely different articles: anybody seen this before?

I'm seeking the collective wisdom on a student paper that is not passing the sniff test. Along with language and content that is far beyond the student's likely ability, and a host of source articles published a few decades ago being used to address a current topic, in reviewing the bibliography I am finding that several of the DOIs provided do not take me to the listed papers. Have you come across this DOI phenomenon? Is this another generative AI creation? Edit. The papers do exist and the DOIs do work, they just take me to completely different papers in about half the bibliographic entries.

Update: students was citing the citations of their source, and Grammarly to "tidy up".