Configured JDK/ANT/MAVEN/Subversion and E-mail notifications settings and a SVN tag job. Then upgraded the subversion plugins and restart Jenkins. Lose ANT, Subversion and E-mail from configure Jenkins and lose SVN tag job configuration.
After that, each restart/reload configure, lose ANT, Subversion, Email and Job settings
There should be warnings or error messages in the Jenkins log, or entries in Manage Jenkins » Manage Old Data.
As it is, this issue report doesn't provide enough information to investigate further, therefore resolving as incomplete.