A hot potato: We're used to hearing stories about China censoring its internet, but it seems the practice appears in North America and Canada, too. That's according to researchers who say Microsoft makes it harder for users in those countries to look up politically sensitive Chinese personalities on Bing.

The Citizen Lab, an interdisciplinary laboratory based at The University of Toronto, analyzed Microsoft Bing's autosuggestion system and found that the names of Chinese party leaders, dissidents, and other persons considered politically sensitive in China were censored from appearing in the search engine's autosuggestions—i.e., they don't appear when users start typing them.

Politically sensitive people are the second-largest category of names censored by Bing's autosuggestion feature—only those relating to eroticism had more.

In tests carried out last year, some of the names that Bing wouldn't fill included Chinese President Xi Jinping, deceased human-rights activist Liu Xiaobo, and Tank Man—the nickname for the protestor who famously stood in front of the tanks leaving Tiananmen Square in 1989.

The censorship applies to names written in both Chinese characters and English letters, and the same issue was found in the Windows Start menu search and DuckDuckGo, which uses Bing's autosuggestion data.

The most surprising part of the investigation is that it appears the censorship applies to regions outside of China, including the United States and Canada. The researchers say this "must be the result of a process disproportionately targeting names which are politically sensitive in China."

Microsoft claims human error was behind the issue, and it has now been addressed. That's the same excuse it gave when Bing was found to be censoring images of Tank Man last year.

"A small number of users may have experienced a misconfiguration that prevented surfacing some valid autosuggest terms, and we thank Citizen Lab for bringing this to our attention," a Microsoft spokeswoman said.

Jeffrey Knockel, senior research associate at Citizen Lab, warned of the dangers that come from censorship rules leaking from one part of the world into another. "If Microsoft had never engaged in Chinese censorship operations in the first place, there would be no way for them to spill into other regions," he said.