Instagram rolled out a 'last active' feature, which shows users you follow when you were last active (i.e. 8 minutes ago, 1 hours ago, etc.) on the app.
The status is displayed underneath the usernames of people you've direct messaged.
Here's how to turn off the privacy invasion feature:
1. Tap the bottom-right profile icon
2. Go into the app's settings
3. Scroll down to "Show Activity Status" and slide the toggle to turn it off.
Note: you won't be able to see other users' active statuses when the feature is turned off.