Poe1 Phrecia Chance to contain Harbinger not working

Hi, on the Poe1 Phrecia event the idol prefix "Your maps have #% chance to contain additional Harbinger" its not working for me. On the stats it shows 543% chance, but when I start the map I get no extra Harbingers from this prefix. Sacarbs and the prefix " Your maps contain an additional Harbinger" does work correctly.