A webmaster asked Google why would Google show more indexed URLs than submitted URLs in the Google Webmaster Tools Sitemaps reporting section?
In this case, Google Webmaster Tools sitemap report showed the webmaster 2,365 URLs submitted with 2,469 URLs indexed. Here is a screen shot:
How can this happen? John Mueller responded on Twitter saying it is a timing issue.
John wrote:
Your sitemap file size has gone down, it looks like it's just a matter of timing (old file indexed counts, vs new submission)
Indeed that was true. Shortly after, Google Webmaster Tools updated the report and the numbers now make sense.
Forum discussion at Twitter.