Phases change in the thunderstorm line

I need the NPC https://www.wowhead.com/wotlk/npc=29504/flaming-geist at the lake in Thunder Ridge, but this location is divided into 3 phases for me:
1. Only Fragile Geists are visible on the lake, and all the giants are lying dead
2. Only Flaming Geists are visible inside the cave itself
3. On a small patch of land between the cave and the lake, I enter a phase where both the giants and Flaming Geists are visible
I need phase 3, but it only works on a very tiny area. Is there any way to fix this so I can see the Flaming Geists across the entire lake?

1 phase: https://ibb.co/qM3qNQqZ
2 phase: https://ibb.co/9kjxmmyn
3 phase: https://ibb.co/ynFTbq4W