Google is being sued by the Republican National Committee, over its email filtering practices. The lawsuit was filed with California’s Eastern District Court on Friday, and accuses the online search leviathan of sending RNC fundraising emails to spam folders in a discriminatory fashion, through its spam filtering algorithm.

The complaint says, “At approximately the same time at the end of each month, Google sends to spam nearly all of the RNC’s emails. Critically, and suspiciously, this end of the month period is historically when the RNC’s fundraising is most successful.”

This is not the first time this dispute has aired. Google had already launched a controversial program when confronted about this same issue in the past. After a study showed that Google’s email service was more likely than competing email clients to filter emails from Republican campaigns, the search giant promised to work with the Federal Election Commission to design a system which would prevent political messages from being directed into spam folders. The concession was designed to stop Republican lawmakers from pursuing a bill they had introduced which would have banned email platforms from routing campaign messages automatically using algorithms.

The Verge however recently reported that the Republican National Committee is not taking advantage of Google’s new program designed to address the Party’s concerns. The lawsuit makes no explicit mention of the program.

The lawsuit continues, “This discrimination has been ongoing for about ten months — despite the RNC’s best efforts to work with Google.”

Regarding the lawsuit, Google said to a reporter from Axios, “As we have repeatedly said, we simply don’t filter emails based on political affiliation,” and that the filtering system reflects the actions of its users.