Now it’s Twitter copying Facebook… but in the worst way. Following several embarrassing disclosures of inaccurate metrics by Facebook, today Business Insider’s Alex Heath broke news that Twitter overcharged some advertisers. Between November 7th and December 12th, a source tells BI that video ad buyers were overcharged up to 35 percent.

Twitter apparently informed these advertisers earlier this week and issued refunds, but didn’t publicly announce anything until after BI’s report today. In a short, extremely vague blog post, Twitter writes that “We discovered a technical error due to a Twitter product update to Android clients that affected some video ad campaigns.” It doesn’t mention that advertisers were over-billed or that they’ve been issued refunds.

VentureBeat reports that some of those refunds might only be $1, indicating at least a portion of those advertisers impacted weren’t running huge campaigns. Still, the news sows distrust in Twitter’s ad platform at a tough time for the company. Sixty percent of its top leaders have left this year, while its share price has struggled and talks for it to be acquired fizzled out.

Live video and the lucrative ads that run with it are Twitter’s big hope, which is why even a minor billing error in this department is problematic.