Coauthor copying text - is it plagiarism, and what should I do?

Question

Someone I coauthored a paper with a couple of years ago has recently posted a new preprint (with some new authors) in which several paragraphs have been copied from this earlier paper; at least two paragraphs have been copied verbatim, with several others copied with only trivial modifications made to certain words. The new paper does cite the old paper, but only in the introduction (i.e. not within any of the relevant sections in which text has been copied), and in particular does not give any indication that any of the text has been copied from elsewhere (e.g. there are no quotation marks, no "as first described in...", etc.).

Here's where it gets slightly more subtle: I actually have proof (in the form of records from our collaborative Overleaf document) that all of this text was written by me, and not by my coauthor. However, despite writing this text, I am not credited anywhere within this new paper, except for the aforementioned citation to our collaborative paper in the introduction (my name does not even appear in the acknowledgements).

A couple of questions, then:

(1) Does this constitute plagiarism?

(2) Irrespective of whether this formally constitutes plagiarism or not, what can/should I do about it (if anything)?

Many thanks!

Answer 1

With or without citation, this sounds like plagiarism. I can't imagine a scenario where copying entire chunks of published text (outside of a direct quote) would be acceptable. And as @Buffy mentioned, there could be some legal/copyright issues on top of the ethical concerns.

You should absolutely contact your former collaborator as well as the other authors. This sounds too egregious be be an innocent mistake but, in any case, the easiest solution would be to get them to fix it before they submit it anywhere. A side note, assuming they want to submit the manuscript somewhere remotely reputable, this would probably be caught by even the most basic plagiarism checkers...

Answer 2

If done without citation it is plagiarism an/or self-plagiarism. But, it might also be copyright infringement if they aren't the copyright holder. If you haven't given up copyright to the earlier paper then you likely still have a copyright interest.

You should just inform them (all authors) of the problem and ask for a fix. Don't just inform your previous collaborator.

It may have been just sloppy work and not an intent to infringe.