Turn on Environment Fog, only one spotlight in the scene.
The Normal one was rendered in the CPU engine. The strange one was rendered in CUDA/RTX.
Dear @hill_lam , hello.
Excuse us for the delayed response.
This is a known issue, already logged in our system with VGPU-5671 number.
I will add now this forum thread to it and you will be notified when a fix is available.
Thanks for sharing though!
Best regards,
TS