Running command fdesetup usingrecoverykey returns true after changing the FileVault2 recovery key.

Number:rdar://FB7800416 Date Originated:6-26-20
Status:open Resolved:
Product:macOS Product Version:10.15,11.0
Classification: Reproducible:yes
After unlocking a machine on 10.15+ using the personal recovery key, running the command ``sudo fdesetup usingrecoverykey `` will show ``true``. But after changing the recovery key and not rebooting running the same command will still return ``true`` even though the machine is no longer unlocked using the recovery key. On previous macOS versions that supported running ``sudo fdesetup usingrecoverykey`` after changing the recovery key it would return ``false``. The current behavior breaks any automation workflow that wants to rotate the recovery key after using it unlock the drive, as it will continue to return unreliable information.

Reproduction Steps:
 - Enable FileVault on a machine running 10.15 or 11.0 with the Personal Recovery option, through System Preferences is fine, take note of the recovery key. 
 - Shutdown the machine.  
 - Type password wrong 3 times
 - Select option that appears to use recovery key
 - Use the recovery key to unlock the machine
 - Change the password, and arrive at the desktop
 - Open and run ``sudo fdesetup usingrecoverykey``, it should return ``true``
 - Now change the recovery key using the following command ``sudo fdesetup changerecovery
-personal`` and follow the prompts entering your username and password 
- You should be presented with a new recovery.
- Now that you’ve changed the recovery key run ``sudo fdesetup usingrecoverykey`` again. It should still return ``true`` when in fact it should now return ``false`` This is new behavior from previous versions of macOS that would return false after changing the key.

Expected Behavior:

After rotation of the FileVault recovery key the command ``sudo fdesetup usingrecoverykey`` should return ``false``

Actual Behavior:
The above command still returns true, even though the disk is no longer unlocked using the old recovery key.

Impact Numbers:
  This behavior affects the 8000 machines we currently run automation on, and tens of thousands of other machines at various companies that try the same automation.


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