FaceApp’s founder Yaroslav Goncharov has apologized for its “hot” filter after some users pointed out it made their skin appear lighter, The Guardian reports. The selfie app uses neural networks to change a person’s appearance by plastering a fake smile onto their face or making them look older or younger. But the app’s hot filter seemingly just makes people look whiter.

“We are deeply sorry for this unquestionably serious issue,” Goncharov said, according to The Guardian. “It is an unfortunate side-effect of the underlying neural network caused by the training set bias, not intended behavior.”

Following his apology, Goncharov said that the filter would remain on the app but would be renamed “spark” in order to “exclude any positive connotation associated with it.” He also said a “complete fix” is in the works, according to The Guardian.

FaceApp has been out for months already, but enjoyed a bit of a popularity bump over the last week, which prompted this response from users.

This is not the first time a photo-editing app has been criticized for its filters. The Chinese selfie app Meitu has an “angelic” filter that also whitewashes users’ features. And Snapchat has made several missteps in recent months, including one filter of a racist Asian caricature and one of Bob Marley.