Win10 64 bit, an ATI 7xxx GPU, 24 gigs RAM, third gen i7 processor
Broken: hash 578f70f
Worked: hash da7ddb6
Short description of error
Very recent tweaks to the new SSS model seems to have introduces what appears to be pronounced steps in the terminator when the radius has different values for the red, green, and blue channels. This did not exist in the initial implementation and is far harsher than simple cubic scattering. This being with CPU rendering by the way).
Exact steps for others to reproduce the error
Download the .blend file and render, here's an image of what to expect depending on the builds (I will also note that there were no settings whatsoever that were changed).
I know the implementation still has a WIP component to it, but I do think the recent tweaks may have made it less correct instead of more.