X$KCCCP corresponds to the checkpoint progress record that you can see in controlfile dumps. The CPODR_SEQ, CPODR_BNO and CPODR_BOF fields correspond to the on disk RBA. The on disk RBA is the redo block address of the last log block written by LGWR. If you switch logfiles using the ALTER SYSTEM SWITCH LOGFILE command several times when there is no redo for LGWR to write, it is possible for the sequence number of the current log file to be well ahead of the on disk RBA.

My understanding of X$KCCCP is that it has the current log file information in it. But mine seems very old:

    SQL> select cpodr_seq, cpodr_bno from sys.x_$kcccp;
    
    CPODR_SEQ       CPODR_BNO
    ----------      ----------
    23904           2658
    
    1 row selected.
    
    SQL> select sequence#, status from v$log;
    
    SEQUENCE#       STATUS
    ----------      ----------------
    23907           INACTIVE
    23908           CURRENT
    
    2 rows selected.