"Add Title to List" behaves differently on Mobile App than Webbrowser

I noticed that I you can add a title multiple times to a list within the browser but when you try to do that within the mobile app you get a notification that the title is already on the list. This is pretty annoying when you're updating your lists in the browser. You'd always have to check if that title is already present to avoid duplicates. IDEA: Add a the same notification to the Website, please.