Mark Zuckerberg has made it his goal to “fix” Facebook. Now his fixes may be causing new problems for the stock with news that time spent on the site has dropped and the first-ever report of a decline in daily users.

Adding to Facebook’s woes: Not catching a fake “supermoon” video on Wednesday.

A Facebook Live video was a still image with wind sounds added was viewed more than 16 million times over four hours on Wednesday, apparently going undetected by the company even as some commenters pointed out that something fishy was going on.

The stream featured a nine-year-old still picture of the moon over the Temple of Poseidon in the south of Greece. The image was overlaid with a current timestamp and the sound of wind was added in an attempt to make it seem live.

The stream appeared as the first video result in Facebook searches for “supermoon.”

The stream was posted on a Facebook page named “EBUZZ,” which despite posting only a handful of times since November 2016 has more than 250,000 followers.

The page appears to be run anonymously, and it does not offer a way to contact its administrators.

The video was removed from the platform by late Wednesday afternoon, but the EBUZZ page itself was still live as of Wednesday night. Facebook told CNN the video was removed for violating the site’s policies. It did not say why the page itself was not removed.

CNN determined that the photo used was taken by Chris Kotsiopoulos, an amateur photographer. Kotsiopoulos told CNN that he had seen instances where his photographs had been used without his permission before, but never in this way.

Facebook troubles

Meanwhile, Facebook’s CEO told investors Wednesday that tweaks made to the content it shows users has led to a notable drop in the amount of time users spend on the social network.

“In total, we made changes that reduced time spent on Facebook by roughly 50 million hours every day,” Zuckerberg said in a statement with the company’s fourth quarter earnings report.

The decline is said to come from a decision to show fewer viral videos in the News Feed.

Facebook also reported its first-ever decline in daily users in the U.S. and Canada. It had 184 million daily users in this region in the quarter, down from 185 million in the prior quarter.

The stock fell 5% in after-hours trading following the report, a rare decline for a company that consistently outpaces Wall Street’s estimates.

Facebook has rattled investors in recent months with a series of announcements in response the platform’s role in enabling fake news, filter bubbles and foreign meddling in the U.S. election.

This month, Facebook announced plans to show users more content from friends in the News Feed and less from brands and publishers in an effort to boost the well-being of users. In particular, Zuckerberg targeted videos and articles that users consume passively, without commenting or sharing.

Zuckerberg previously said the change could lead to a drop in user engagement and time spent on the platform, but would ultimately improve the quality of the user experience.

Ad sales remain strong

The move raised concerns among investors about the impact on Facebook’s core advertising business. For now, Facebook continues to be an ad sales juggernaut.

Sales hit nearly $13 billion for the quarter, an increase of 47% from the same period a year earlier. The company now has 2.13 billion monthly active users and 1.4 billion daily users, and advertisers are eager to reach that massive audience.

Earlier this month, Zuckerberg said his personal goal for 2018 is “fixing” Facebook’s many problems. He cited the need to “protect our community from abuse and hate, defending against interference by nation states” and “making sure that time spent on Facebook is time well spent.”

In November, he said the company is “investing so much in security that it will impact our profitability.” That investment includes doubling the number of people who work on safety and security to 20,000.

The announcement came on the same day that executives from Facebook, Google and Twitter testified before Congressional hearings into how Russian actors used social media to meddle in the 2016 presidential election.