**System Information**
Operating system: Darwin-19.4.0-x86_64-i386-64bit 64 Bits
Graphics card: Intel(R) Iris(TM) Plus Graphics 640 Intel Inc. 4.1 INTEL-14.5.22
**Blender Version**
Broken: version: 2.90 (sub 0), branch: master, commit date: 2020-04-17 20:06, hash: `rB0fe8239470ac`
Aslo tested on 2.82a
**Short description of error**
Material rendering not properly on Cycles rendering
**Exact steps for others to reproduce the error**
"SolarPanel" material always black on Cycles. Only Emission and Alpha properties work's right.
Deleting face and create new one helps.
{F8483444}