as shown in the attached images I have black (shadow?) artifacts in my fire animation. Some frames are fine, like the left one. Some frames have these black patches. The patches move and appear on the walls of the chimney.
The fire is build with a smoke domain, a particle and smoke emitter, and the woodlogs. The upper woodlog is set to smoke collision. I also put a yellow lamp between the woodlogs to increase the fire glow and set the woodlogs as well as the particles to throw no shadows. The animation of the fire .blend file is fine. But when I link the fire .blend file to the chimney .blend file, these black patches appear.
Thank you in advance for any hints on how to solve this.