Crosscheck mark as expired a backup with KEEP UNTIL TIME 'sysdate + 365' a day after

I took a backup yesterday (jan,31th) with 

run {

allocate channel t1 type 'SBT_TAPE';

allocate channel t2 type 'SBT_TAPE';

send 'NSR_ENV=(NSR_SERVER=tfsnbk01,NSR_DATA_VOLUME_POOL=TFMonthly)';

backup as compressed backupset database TAG = 'Monthly_DB' KEEP UNTIL TIME 'sysdate + 365';

backup archivelog all TAG = 'Monthly_ARC' KEEP UNTIL TIME 'sysdate + 365';

release channel t1;

release channel t2;

}

Today, Jan, 1st  I run a crosscheck and it marked the backup as expired.

981     B  F  X SBT_TAPE    31-JAN-12       1       1       YES        MONTHLY_DB

982     B  F  X SBT_TAPE    31-JAN-12       1       1       YES        MONTHLY_DB

983     B  F  X SBT_TAPE    31-JAN-12       1       1       YES        MONTHLY_DB