I configured one of my jobs with the SVN URL http://Subversion/svn/.... The job was building correctly. The job was configured to check every 5 minutes for updates. Every time it checked the pulling log said something along the lines of "Workspace doesn't contain information about http://subversion/svn/...." and build the job again. The changes link just informed me that there were no changes.
When I finally changed the SVN URL to http://subversion/svn/.... the job stopped building every 5 minutes (288 builds per day).
I think the check for updates should ignore the case of the Server part of the URL.