Things just keep getting worse for Facebook this week as Mark Zuckerberg heads to Capitol Hill to testify about his company’s many ongoing privacy controversies. And one of the biggest scandals plaguing the site got even bigger when it was revealed that the private contents of about 1,500 users’ messages were obtained by Cambridge Analytica in the data breach last fall.

Facebook slipped this fact into the notifications it began rolling out to the estimated 87 million users who were affected by the breach. According to the company, about 1,500 people granted permission to the shady app at the heart of the scandal to access the private contents of their messages. That also means that anyone who messaged with those users also had their messages exposed. This is bad enough on its face, but as one expert pointed out, it’s also disturbing that Facebook seemed to reveal this problem quietly so as not to draw attention.

“The harvesting of personal Facebook messages wasn’t disclosed, yet again, until the last second,” Jonathan Albright, a digital journalism research director at Columbia University, told WIRED. “I suspect it’ll be difficult to accurately reconcile the number of users affected due to the nature of [direct messages] and especially group messages.”

At least Zuckerberg is already in Washington D.C. to answer questions from lawmakers — because it seems as though his problems aren’t going to end anytime soon.