When you create a Spotlight connection to the production database, you also install a Spotlight user on the database. In doing so, Spotlight makes changes to the SYS schema of the database by creating a number of x$ views. These new views, when copied to the STANDBY database, are labeled as invalid, and will prevent a user from opening the STANDBY database.
STANDBY database does not inherit the Spotlght objects to be transferred as 'valid'.
You need to drop the Spotlight x$ views by using the script attached logged on as SYSDBA via SQL PLUS on the Production database if intend to take the Production database offline.
If the PRODUCTION database fails unexpectedly, and you need to use the STANDBY database, you must first log onto the STANDBY database via a SYSDBA account and drop the Spotlight x$ views.