Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2070 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.09
Broken: version: 2.92.0 Alpha, branch: master (modified), commit date: 2020-11-02 19:31, hash: rBb9ec6c305cc8
Also tested on 2.83.8 and same problem.
Worked: It do not think this has ever worked
Short description of error
When reverting to the Default Value for Viewport Display Color the alpha gets down to 0.8 making the object semi transparent.
Exact steps for others to reproduce the error
Open up a new scene.
Select the cube.
Go to the materials tab.
Scroll down to "Viewport Display"
Right Click on "Color"
"Reset to Default Value"
Result: RGB values go back to the default, but Alpha goes to 0.8
Thank you so much !