Oracle Database 12c -- V$RECOVERY_FILE_DEST shows wrong results

Problem

Column SPACE_USED of V$RECOVERY_FILE_DEST shows wrong information, either more or less than the actual size of the files on the file system

Solution

To reset the information in V$RECOVERY_FILE_DEST use:

SQL> alter session set events 'immediate trace name kra_options level 1';

Optionally after that, execute:

SQL> execute dbms_backup_restore.refreshagedfiles;