Windows 10 64
Intel i5 6400
Short description of error
Using the subsurface on Principled BSDF shader, the first few samples cause colored noise, only if the radius are 0 and branched pathtracing is used. See attached image. It eventually converges after some samples but I guess is worth reporting just in case.
Exact steps for others to reproduce the error
Add a Principled BSDF shader, turn Subsurface to 1, turn all sss radius to 0, change integrator to Branched path tracing
Or open the attached .blend file