When trying to shorten a URL in Bitly, you may try and submit a URL that is percent encoded—that's when you copy a URL and it includes characters with percent symbols, like "%3A%2F%2".
When percent encoding is used we unescape/normalize the URL on the backend and return it to you.
The normalized version of the URL looks different than the percent encoded version but it’s important to note that even if it looks different they are the same thing. There may arise issues possibly because servers might expect a percent encoded URL which we won’t return. If that’s the case, then you should just correctly handle the normalized version of the URL (which is a perfectly valid URL) that we return.