The postcard featuring an aerial view of the Plaza de la República in Buenos Aires was meant as a thoughtful gesture from a longtime friend.

But as it made its way from Argentina to Toronto, its error-laden English provoked someone to take to the text with a red pen, correcting errors and scrawling a note that read: “ps Learn English!!”

The act left Mirella Zisko stunned. The postcard had been sent to her by a former colleague, now in his 60s, who had emigrated to Canada from Argentina and learned English as a second language.

The postcard. Photograph: Lorenda Reddekopp/CBC

Oscar’s original message – “I west thinking in you, Have a nice day” – had been marked up with red pen, much like how a teacher would tackle a student’s essay.

His words had been crossed out to adjust the message to “I was thinking of you.” The meddler had also added their own note to the postcard – “Learn English!!” – directed at Oscar and underlined twice for emphasis.

“First I was mad and then I just felt upset for him,” Zisko told the Canadian Broadcasting Corporation. “He’s such a good friend and he’s an older gentleman and I just felt hurt for him that someone would go out of their way to be mean.” She hadn’t had the heart to tell him what had happened to the postcard, she added.

The act drew fury from her university-age daughter, said Zisko. “She’s like, ‘This is wrong, this is racist. It’s 2017. Who has the right to do this?’”

While it remains unclear where exactly in the mailing process the postcard was tampered with, Zisko has filed a complaint over the incident with Canada Post. The corrections were more likely to have happened in Canada, she reasoned, than in Spanish-speaking Argentina.

On Thursday, the postal operator called the incident “an extremely rare occurrence” and said it was continuing to monitor the situation.

“It is truly unfortunate that Ms Zisko’s postcard was marked-up and we can certainly understand why she would be upset,” a spokesperson for Canada Post said. “With many hands touching the postcard before and after it entered Canada, it is impossible to determine where and when the marking may have occurred.”