Activewear brand Lululemon is in hot water in China after a promotional event held on the Great Wall appeared to mistakenly feature a Japanese drum – setting off an online furor.

The consumer backlash, which prompted Lululemon to issue an apology and scrub its campaign, is the latest example of how quickly Western brands can come unstuck in a country where nationalism has surged under strongman leader Xi Jinping.

It began with a yoga festival organized by Lululemon on the Great Wall on May 30, according to Chinese state-run tabloid Global Times.

Billed as an event promoting Chinese culture and wellness, more than 2,000 guests laid down their mats on the ancient stone of the country’s most iconic landmark to practice yoga under the sun, according to a now-deleted press release by the brand.

One prominent guest was Chinese actor Zhu Yilong, known for his roles in popular movies and television shows like “Guardian,” “The Story of Minglan” and “Lighting Up the Stars.” At the festival, he joined a drum troupe in performing on what was initially described as a traditional Chinese drum, Global Times reported.