Instagram is preparing a new feature that locks the old version of your username for 14 days the moment you change your username. The goal is to prevent someone else from taking over your old user ID right away.
Users usually decide to change their Instagram username when they take a new step in their life, such as getting married, choosing a new surname, moving, or modifying their account for another reason. But if you decide to modify your username on Instagram, someone else could use your username, and you won’t be able to get it back.
The new Instagram feature will lock old usernames for 14 days so you will not lose your original name if you change your mind in the meantime.
Instagram wants to implement the new feature mainly because robots (grabber bots) can take advantage of the situation and take your old username. When this happens, you don’t have a chance to return to the old ID.
Instagram commented on the upcoming feature, saying that they were following trends and aimed to create tools to keep the community safe.