But when I register new trainees that meet the same criteria, the PI does not get updated. I have run analytics twice, but the PI stills shows the same result: 8. I do know if the problems is the PI itself or not.
It depends on how often you load your analytics. Quote from the documentation “If you are loading data continuously into the analytics tables, select No cache”. But it might stress your server performance. When we are doing some test we set it as No cache whereas normally we have set it for one hour (we run analytics once a day).
Try setting it as No Cache and run analytics again, values should be then updated.