Missing controlfiles ?

During the backup check this morning, I noticed something strange..
The backup logfile was showing the following error :

Starting Control File and SPFILE Autobackup at 10-12-2012 01:46:29

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03009: failure of Control File and SPFILE Autobackup command on ORA_DISK_1 channel at 12/10/2012 01:46:31

ORA-19504: failed to create file "+FRA/ngp01/controlfile/c-1446976194-20121210-02"

ORA-17502: ksfdcre:4 Failed to create file +FRA/ngp01/controlfile/c-1446976194-20121210-02

ORA-15173: entry 'ngp01' does not exist in directory '/'

I fist checked if the directory really did not exist in ASM.

Using the ASMCMD, it seems the directory is not there.

ASMCMD> ls FRA
NGP01I/
NGP02I/

But checking the status of the controlfile in the database :

SQL> select name from v$controlfile;

NAME
--------------------------------------------------------------------------------
+NGPDATA/ngp01/controlfile/current.263.796827271
+FRA/ngp01/controlfile/current.3434.796827271
 
Same directory that does not exist according to RMAN (and I can't see it neither in ASM)

Still, the database is running.... No errors in the alert about missing controlfiles. How can the database be running normally with controlfiles that we and RMAN cannot see ??

Update
Could it be possible the files still exist in the ASM cache ? The database is running fine, I also executed a backup controlfile to trace, and this file looks good. So, it seems the controlfile is online for the database  (11.2.0.1.0), but it's no longer present on disk. So, what is the database using and updating ?