Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: GeForce GTX 980 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 419.35
Broken: version: 2.80 (sub 54), branch: blender2.7, commit date: 2019-04-07 00:43, hash: rBd2d84132ddf9
Worked: version: 2.80 (sub 51), branch: blender2.7, commit date: 2019-03-24 00:06, hash: rB79f67acccb36
Short description of error
so the bottom line of this seems the be the 4th input "Density Attribute" on the "Principled Volume" Shader. When adding this Shader the Density Attribute is pre-set to "density" which did not cause any issue on the "Worked version" mentioned above.
However, on the newest build "broken" having this default value "density" filled in prevents the Principled Volume Shader from working at all. Removing the value fixes the issue.
This should not happen considering it comes with this value prefilled by default.
"Principled Volume" node not working anymore in EEVEE.
"Volume Scatter" node works.
"Principled Volume" works fine on 79f67acccb36 from 24th march.
Exact steps for others to reproduce the error
plug "Principled Volume" into World Volume.