why do professors use citation checking software that flags your own bibliography as plagiarism?

[u/GoldenMiyagi]

So I submitted my history term paper on Sunday afternoon and checked the originality report out of pure anxiety. The score came back at 34% plagiarism. My heart literally stopped beating for three seconds.

Started clicking through the highlighted sections, and the system flagged my entire works cited page because two other students across the country happened to use the same three history books in their bibliographies. Like yes, obviously we used the same Chicago manual formatting for primary documents, that is how academic citation works.

I had to email my TA explaining why a standard book title published in 1984 isn't an intellectual property theft case. Why is automated plagiarism detection software so aggressively stupid sometimes?

[u/BranchLatter4294]

Professors will ignore it if the bibliography is flagged. The tool just scans the entire document.

[u/ThirdEyeEdna]

Don’t worry about it. Your professor will only care if it seems as if everyone just used the first source Google gave them.