When a reverted file is committed to svn, the updated Jenkins workspace will get the timestamp from the original file instead of the update time. This is a known issue in SVNKit and has already been fixed, see details at: http://issues.tmatesoft.com/issue/SVNKIT-322

The SVNKit version 1.7.6 that the subversion plugin is using is still affected by this bug. Because this is a major issue for any incremental build system that uses timestamps (and because I just spend a lot of time debugging this problem) I decided to duplicate the issue here.