Nvidia NVDA shares dipped about 3% on Thursday after a federal judge certified a class-action lawsuit alleging the company misrepresented its cryptocurrency mining-related revenue during the 2017-2018 boom.

The suit claims Nvidia understated its exposure to the volatile crypto market by classifying more than $1 billion in GPU sales to miners under its Gaming segment. Plaintiffs argue the company told investors that crypto mining accounted for only a small portion of its business when internal documents suggest otherwise.

When crypto prices crashed in late 2018, Nvidia slashed its revenue forecast and its stock fell more than 28% over two trading days. Judge Haywood S. Gilliam Jr. certified the class after determining the company had not…