Apple is censoring words and phrases relating to politics, religion, democracy, and human rights — which customers can engrave on its products — in mainland China, Hong Kong, and Taiwan, CitizenLab has revealed.

An interdisciplinary laboratory based at the Munk School of Global Affairs & Public Policy, University of Toronto, CitizenLab’s research found that part of Apple’s mainland China political censorship bleeds into both Hong Kong and Taiwan.

“Much of this censorship exceeds Apple’s legal obligations in Hong Kong, and we are aware of no legal justification for the political censorship of content in Taiwan,” said the report that came out on Wednesday.

An analysis found that the company filters 1,045 keywords in China, compared to 542 in Hong Kong, 397 in Taiwan, 206 in Canada, 192 in Japan, and 170 in the US.

“We present evidence that Apple does not fully understand what content they censor and that, rather than each censored keyword being born of careful consideration, many seem to have been thoughtlessly reappropriated from other sources,” the team noted.

“In one case, Apple censored 10 Chinese names surnamed Zhang with generally unclear significance. The names appear to have been copied from a list we found also used to censor products from a Chinese company,” they added.

Keywords filtered in China include politics, resist, wave of democracy, and human rights.

For AirTag engravings limited to four characters, Apple does not allow response to the “8964” engraving. The error message says: “Please resubmit your engraving message. Personalize with your initials, lucky numbers, and favorite emoji.”

The 8964 number refers to the Tiananmen Square protests, which took place on June 4th, 1989.

In Hong Kong, banned phrases include double universal suffrage, Umbrella Revolution, and freedom of the press for engraving.

In Taiwan, Apple customers are not allowed to reference high-ranking members of the Chinese Communist Party or the banned religious movement.

Apple responded to CitizenLab report, saying: “We try to not allow requests which could represent trademark or intellectual property violations, are vulgar or culturally insensitive, could be construed as inciting violence, or would be considered illegal according to local laws, rules, and regulations of the countries and regions where we personalize and where we ship.”

“We handle engraving requests regionally. There is no single global list that contains one set of words or phrases. Instead, these decisions are made through a review process where our teams assess local laws as well as their assessment of cultural sensitivities,” said Apple’s chief privacy officer Jane Horvath.

“To a large degree, this is not an automated process and relies on manual curation. At times, that can result in engraving requests being mistakenly rejected and we have a process in place to review and correct those situations when they occur,” Horvath added.