In what has to be in the running for the most baffling move by a social media platform in 2018 (though Facebook has that award locked up already), Instagram began rolling out a new feed for some users this week which forced them to scroll through their friends’ photos horizontally rather than vertically.

Instagram first began testing this feature in October, but at the time, it was restricted to the Explore tab. In that section of the app, it made a certain amount of sense — after all, you are just poking around, checking out random posts from strangers anyway. But on Thursday, some users began seeing a horizontal feed as soon as they opened the app. In effect, the entire feed turned into a Story, with tap controls as well as a progress bar up top.

There are plenty of explanations for why Instagram would shift to the horizontal feed as its default layout, chief among them being that each individual post is given far more focus than it would be if you were just absent-mindedly scrolling down your feed at warp speed. And some of those posts happen to be ads.

The new layout also makes comments more prominent, as you can simply swipe up at any time while viewing a post to access them. And if you want to see Stories, just swipe down instead. The horizontal feed seemingly only affected the main feed while it was active, as user profiles still used the standard scrolling feed.

You might notice the past tense scattered throughout this post, and that’s because while I was writing it, Instagram seemingly reverted everyone to the classic vertical feed. Head of Instagram Adam Mosseri explained on Twitter that “this was supposed to be a very small test but we went broader than we anticipated.” In other words, only a few people were meant to see this, as opposed to the thousands who received the update.

That’s the good news, but the bad news is that Instagram is clearly strongly considering making the horizontal feed a reality for all users in the near future. If the test is an utter failure, and the reaction is as negative as it appeared to be Thursday, perhaps we can dodge this bullet, but widespread disapproval hasn’t always stopped social media platforms in the past. In the meantime, enjoy your vertical feed while you still can.