
Back in October 2017, Facebook made one big change to its News Feed.
At the time the social giant thought that by splitting it into two: from friends and the other one from non-promoted Pages and publishers (called 'Explore'), can help users in getting relevant information while negating fake news. Facebook’s head of News Feed, Adam Mosseri, said the experiment was motivated by “consistent feedback” that people wanted to see more from friends and family and less from media organizations and businesses.
The test was made in six countries: Bolivia, Cambodia, Guatemala, Serbia, Slovakia, and Sri Lanka.
But the results weren't as Facebook expected; the company realizes that the move was all wrong.
Read: Facebook Updates News Feed, Affecting Organic Post Reach Of Business Pages

Aside from criticisms from news organizations, Facebook found that separating the feeds didn’t really lead to increased connections with friends and family as it had intended. What's more, It’s worth noting that people in those five countries didn’t receive important information that they needed after the change took effect, and for that matter, they had no idea what was going on with their feeds.
This resulted to a blunder.
On March 1st, 2018, Mosseiri admitted Facebook's failure in this experiment, saying that:
"You gave us our answer: People don’t want two separate feeds. In surveys, people told us they were less satisfied with the posts they were seeing, and having two separate feeds didn’t actually help them connect more with friends and family."
"We constantly try out new features, design changes and ranking updates to understand how we can make Facebook better for everyone. Some of these changes—like Reactions, Live Video, and GIFs— work well and go on to become globally available. Others don’t and we drop them. Today, we’re ending one of those tests: the Explore Feed."

Mosseri acknowledged that Facebook has learned its lesson from this failure. For that matter, the company will try to provide better communication on changes it's making in the future.
This is an example of an implementation recognized as tone-deaf and based on ignorance. No users in any countries should become unwitting A/B testers in a grand design, without any prior information.
To be clear, this change does not impact Facebook in changing the way it prioritizes "meaningful social interactions," a strategy that aims to feature more posts from friends and family, and show fewer updates from media organizations and business.