I have noticed that some websites like Instagram and ask.fm, google does not update their search results.
For example if i have an instagram username like "Qwerty" then i type Qwerty into google (and since google crawls through instagram for usernames) you should get like:
Qwerty (@Qwerty) • Instagram photos and videos.
And when you change your username to "Asdfgh", google should update the results after some days. So that when you type Asdfgh into google you should get this in the search results:
Asdfgh (@Asdfgh) • Instagram photos and videos
But somehow, they don't update. Even after half a year.
Best Answer
It depends on when Google crawl and update the change you made. This can be fast like a few hours, or can be longer such as months, depending on the website you are in. But generally, websites like Instagram, Twitter or Facebook - Google crawls the changes frequently, so your change will be updated soon.
In the past, Google allows users to input an URL you would like to tell Google to update, but now this function is discontinued.
For more information on how Google bot works, check these sources: