On Holdings was hit with a class action lawsuit filed in the U.S. District Court in Oregon, alleging that the Swiss-based company’s shoes produce a “noisy and embarrassing squeak” not covered by the company’s warranty.

“No reasonable customer would purchase shoes as highly priced as Defendant’s—or paid as much for them as they did—if they needed to make DIY alterations to make the products wearable, or cease wearing them completely due to the squeaky noise defect,” the lawsuit said.

On CloudTec’s technology platform features hexagonal or, in some cases, octagonal or oval holes in the sole. The lawsuit’s plaintiffs allege that the sneakers are so noisy that they are unwearable without “significant DIY modifications.”

In court documents, one plaintiff, Louis Bologna, alleged that he wore the shoes for three months before he noticed “a squeaking with every step that he has been unable to stop.”

Bologna no longer wears the shoes due to embarrassment and annoyance and charged that he would not have paid as much as he did for the shoes if he had known about the “immense squeaking.”

Another plaintiff, Patricia Ramirez, noticed the squeaking after wearing the shoes only three times and said she is also now unable to wear them. She also called out the premium price paid for the shoes.

Court documents further pointed to several Reddit threads calling out the issue, as well as TikTok videos and web pages dedicated to DIY solutions intended to help customers stop the squeak. The lawsuit cites multiple online reviews and customer comments claiming they contacted the company about the issue and were told it does not fall under the company’s warranty.

On said it does not comment on ongoing legal matters.