Instagram briefly switched to a horizontal feed and people freaked out, The new layout was caused by a bug, according to the company.

Instagram has quietly started testing a horizontal feed for some users, a huge sideways shift from the vertically-scrolling user experience that’s been the norm since the app launched. The company had previously been testing the feature back in October in the Explore section of the app, but it seems that it’s rolling it out more widely to users’ main feeds today.

The new feed basically turns all posts into a single, giant Instagram story, complete with tapping to advance and a scrolling bar at the top to show you how far you’ve progressed. With the horizontal feed, each photo (and each ad) is given the spotlight at any given time — you can only view a single post, and the comments are much more prominent now, appearing with a flick upwards.

It’s also much harder to quickly fly through your feed with the new layout: you can only advance a single post at a time. Another side effect of the new layout is that stories are easier to access, with the bar now always available by swiping down, instead of requiring that you scroll all the way to the top of your feed.

The new horizontal layout seems only to effect the main feed — tap into a user’s individual profile, and things will appear as they always have in the usual, vertically scrolling style.

Accordig to Instagram the horizontal feed was meant to be “a test” that went broader then they anticipated.

“Due to a bug, some users saw a change to the way their feed appears today. We quickly fixed the issue and feed is back to normal. We apologize for any confusion.” Says a facebook spokesperson.