Windows 10 64bit AMD ryzen 7 1700 32GB DDR4, 2x GXT1070
Windows 10 64bit i7-5820k 2xGTX960
tested on a couple of different machines
Short description of error
When using Principled shader Diffuse Indirect pass yields different results using Path Tracing or Branched Path Tracing.
When diffuse bounces are 0 Principled shader still appears in Diffuse Indirect pass with Path Tracing mode.
if pricipled shader roughness is at 0 both yield the same result
switching to cpu/gpu or experimental feature set doesn't affect it at all.
Exact steps for others to reproduce the error
-make a simple scene with objects using principled shader (default settings)
-drop diffuse bounces to 0
-enable diffuse indirect pass
-render image with both Branched Path Tracing and Path Tracing modes