Drain Essences modifier Hungering Reach?

Grim Dawn Classes, Skills and Builds
1

At 22/12 it says it has a 35% chance to effect more targets. When does this chance roll?
On Initial Cast only?
or does it have chance to roll every 0.3 seconds (Drain Essences Cooldown)

2

Only on initial cast doesn’t make much sense so most likely the latter

3

With each tick it has a chance to extend to another enemy.

4

Thanks Norzan