Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.09
Broken: version: 2.91.2, branch: master, commit date: 2021-01-19 16:15, hash: rB5be9ef417703
Worked: (newest version of Blender that worked as expected)
Short description of error
There is a big difference in rendered preview with the optix denoiser between version 2.83.10 and 2.91.2. As you can see at the picture below, 2.83.10 do ton render glitches in the darker background. But the same scene with same optix denoiser in viewport does.
Exact steps for others to reproduce the error
The only special thing in the scene is the area light with the power of (- 1 MW) .. yes minus one megawatt for generating darker places. Other is basically standard, some emissions and area lights.
there is the file I am working with. Tried even with the geforce rtx 3080 - same problem.