This is basically just a bug with Instagram. It can be caused by a few things: Not having an updated version of the app, or a fully updated browser if you are using Instagram in browser. Getting too many likes in a short period of time.

• Only your approved followers can see your posts, including any likes and comments.
• When you like a public post, your like will be visible to everyone and your username will be clickable below the post, but only approved followers can see your posts.