In my opinion, those wrong characters are probably coming from some OCR software used on badly scanned books. Those "several students" probably all used the same text database which has this particular issue.
I sometimes see an acute accent used instead of an apostrophe in reddit comments. People aren't scanning old books into reddit comments. It's the keyboard layout.
Also the article author seems to be pretty confident in his ability to detect plagiarized content, and didn't seem to think that stuff was plagiarized.
I personally sometimes type the acute accent instead of an apostrophe. I have the Spain Spanish keyboard installed in Windows in addition to the American English keyboard. I meant to install the Mexican Spanish keyboard but installed the Spain Spanish keyboard by mistake. It was many months until I realized my mistake, and by then I was more used to the Spain Spanish layout than the Mexican Spanish layout, so I kept it. When I'm practicing Spanish I switch to the Spanish keyboard, and often forget about it, so then type an acute accent when I want to type an apostrophe.
Also the article author seems to be pretty confident in his ability to detect plagiarized content, and didn't seem to think that stuff was plagiarized.
I personally sometimes type the acute accent instead of an apostrophe. I have the Spain Spanish keyboard installed in Windows in addition to the American English keyboard. I meant to install the Mexican Spanish keyboard but installed the Spain Spanish keyboard by mistake. It was many months until I realized my mistake, and by then I was more used to the Spain Spanish layout than the Mexican Spanish layout, so I kept it. When I'm practicing Spanish I switch to the Spanish keyboard, and often forget about it, so then type an acute accent when I want to type an apostrophe.