When do the Team Rocket Grunts at Mt Ember battle you in LeafGreen and fire red?

You encounter Team Rocket Grunts at Mt. Ember in both FireRed and LeafGreen after defeating the Gym Leader in Cinnabar Island.

Specifically, you encounter them before entering the Mt. Ember cave.

Here's a breakdown:

1. Defeat Blaine, the Cinnabar Island Gym Leader.

2. Proceed to Mt. Ember.

3. Team Rocket Grunts will challenge you before entering the cave.

They'll be blocking the path, so defeating them is necessary to progress through the mountain.