The direct lights are usually much smoother and with
higher dynamic range than indirect lighting. Using
the R11B11G10 float format exhibit color shifts and
banding even in simple setups without a way to mitigate
the issue.
Using RGB9_E5 encoding improve the quality while retaining
the storage benefit of 32bit formats. The added overhead
of the software encoding not perceptible in a full lighting
pass.
This affects direct lights and SSS convolution result.
Fix#121937
Pull Request: https://projects.blender.org/blender/blender/pulls/122515
3ed825f981