While creating a new RSS Feed Builder and unchecking the "Diff" box, the Changes between revisions still exists in the RSS feed result.

Below are the steps to reproduce the problem:

1. Open the RSS Feed Builder and try creating the RSS feed with the following options:

   Types of content: Pages (only)
   For Pages, show: Content (only)
   From Space(s): <spacename>
   

2. Create the RSS Feed
3. Drag or copy the link displayed into your RSS reader
4. The content still render the Changes between revisions<older> and revision<newer> session in the RSS feed result.

Having the "Diff" option being tick or untick shows no different to RSS Feed result.