WORKAROUND:
1. Close Spotlight;
2. Backup {Spotlight on Oracle folder}\Console\Templates\SoU.STX to another folder (make sure it is backed up to a folder outside Spotlight folders)
3. Copy the attached file to this folder;
4. Open Spotlight and the SoU connection, right click the Disk I/O flow and a new alarm will appear.It is disabled by default, enable it and customize the thresholds if needed;
5. Check if the alarm raised as expected.
SOLUTION
Waiting for a fix in a future version of Spotlight on Oracle.