LOG_ARCHIVE_DEST_N are NULL for my Other Stanby Databases

My Data Guard log_archive_Dest_n parameters are null in my target standby database except the one for my Primary database. It looks the Broker reset them. See MOS 1364467.1

But after a Swicthover and back, they are all null except for the Primary database 

WMRTPRD - Prmmary database

At switchover time they were.

Using the Broker to maintain everything

log_archive_dest_1       = "LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=WMRTPRD3"

log_archive_dest_2       = "service="wmrtprd2_cwy""

log_archive_dest_2       = "LGWR ASYNC NOAFFIRM delay=0 optional compression=disable max_failure=0 max_connections=1 reopen=30 db_unique_name="WMRTPRD2"                                    net_timeout=30"