Instagram experiments with a few new features, with changes and additions that might not always be in the best interest of the end user.
One major feature involves allowing your friends and everyone else in your inbox to see when you last went online. The rollout for this update has been silent, making it possible that people might not notice it exists. It does sound like a privacy concern, so fortunately you can turn it off in-app. Just make sure to visit the Options menu on your profile tab.
The second major feature coming to Instagram notifies a user when another person takes a screenshot of their story. For now, Instagram will give the user a warning, but on the second instance, the person posting the story will get a notification. Again, this may come off as a privacy violation, but for now, we’ll see how Instagram handles things.