Facebook isn’t the only company suffering ad metrics blunders. Now, a relatively large oversight on Twitter’s part has come to light.

The social platform inflated video advertising metrics by as much as 35 percent, according to a person familiar with the matter who spoke to Business Insider. Twitter notified advertisers about the blunder earlier this week, blaming it on a bug in its Android app. It has even issued refunds to marketers for overbilling them for campaigns that ran on its platform between November 7 and December 12.

In a statement, a Twitter spokesperson confirmed the error to Business Insider. “We recently discovered a technical error due to a Twitter product update to Android clients that affected some video ad campaigns from November 7 to December 12,” the spokesperson said. “Once we discovered the issue, we resolved it and communicated the impact to affected partners. Given this was a technical error, not a policy or definition issue, we are confident it has been resolved.”

Similarly, Facebook’s recent history of metrics mishaps was kicked off with a miscalculation regarding video viewing times. It has also suffered errors in regards to its Instant Articles publishing feature on iOS.

Twitter’s advertising revenue totaled $545 million in its most recent quarter, marking an 8 percent increase year-over-year. Mobile advertising made up the overwhelming majority of that amount, at 90 percent. However, the company has previously noted that brand spend isn’t growing as quickly as expected.

Additionally, Twitter has faced its fair share of highly publicized struggles this year. Chief among them was its failed attempt at offering itself up for a takeover or merger. The platform’s stagnant user base (which currently stands at 317 million) is also cause for concern for its shareholders, with users creeping up just 3 percent year-over-year at last count.