Currently there are 9 slots in PoP among which 3 are permanent and 6 are ones that changes every week. Dew to the addition of new PoP tasks many of the rewarding tasks which gives Kobans or Epic Orbs are very rarely showing up. I haven't gotten any Orb task for last 3 weeks. If there are more slots created there would be a better chance of getting at least one of those tasks.