Optimization - high CPU usage even when there's no action going on the screen

Some maps have a VERY high cpu usage for some reason, causing a lot of stutters and FPS drops even when there's no enemies or skills on the screen, while others runs perfectly fine even when there are a lot of enemies, particles and visual effects

One of the few maps i noticed this are Temple of Kopec, Dreadnought Vanguard, Matlan Waterways

I'm on the recommended system requirements and have no other processes in the background and still having this problem sometimes