Operating system: elementaryOS 0.4.1
Graphics card: GTX1080
Broken: 2.80, c041e10c9a94
Worked: 2.80, ff90589966ef675365e06aed804aa02ba2ddc2aa
Short description of error
If you mirror the instance of an object, it gets displayed with wrong, darker shading.
Happened with this commit: ddb71e8c20c2ceba61b4ebddc602adc5b8eed5c8
Exact steps for others to reproduce the error
Here's a file, based off the startup file with a mirrored instance. It gets displayed dark here, while the original cube looks correct, even if I mirror it.