This may be caused by two things:
Solutions:
Disable NVIDIA AI Denoising completely.
Note: it has to be disabled in two places to disable it for interactive and non-interactive rendering:
- Render Settings > Corona > General Settings > Denoising > Mode (set to "None" or some other denoising type)
- Render Settings > Corona > Performance settings > Interactive rendering > "Fast preview denoise during render" mode (set to "None" or some other denoising type)
2) Image upscaling factor
Solution:
You can disable the image upscaling factor in the Corona menu > Preferences > Corona > Interactive Rendering > Image upscaling factor (set it to 1.0).
See: What is Image upscaling factor?
If the above solutions did not help, please contact us about your issue.