When a user is logged in with Adguard enabled and another user then switches to their login via fast user switching whom also has Adguard enabled, Adguard will be disabled for the first user.
To recreate:
Login with a user and enable Adguard.
Login with another user and start Adguard.
Switch back to the first user. Adguard will be disabled for the first user.
To recreate:
Login with a user and enable Adguard.
Login with another user and start Adguard.
Switch back to the first user. Adguard will be disabled for the first user.