Aftershock support with Falling Thunder - why doesn't it work??

Hi, I'm enjoying PoE2 I'm sorry if many of you aren't. The only vexing thing for me right now is why Falling Thunder doesn't seem to work with Aftershock support (20% chance for slams to activate twice)

I have used it dozens of times now and it just doesn't do anything! Is this intentional??

You require power charges in order to fire the lightning projectiles forwards from the impact. To replenish power charges, you need to use skills or abilities that specifically generate power charges, typically by dealing damage to enemies, triggering specific effects on your character, or utilizing gear with power charge generation properties; essentially, you need to actively fight and perform actions that are designed to build up power charges while you play.