When the Potion ingredient draw pile runs out, when do you refill it from the discard?

Question

Accepted Answer

Immediately, as soon as the draw pile is empty: the discarded ingredients are shuffled and become the new draw pile. Shelves are still filled only in the end-of-turn step.

Harry Potter: Hogwarts Battle

When the Potion ingredient draw pile runs out, when do you refill it from the discard?

Harry Potter: Hogwarts Battle

When the Potion ingredient draw pile runs out, when do you refill it from the discard?