Prefab asset preview appears in cyan color when a project is upgraded from 2019.1.0a7 or earlier versions to 2019.1.0a9

Steps to reproduce:
1. Create a project in unity 2019.1.0a7 or earlier versions
2. Create any unity primitive
3. Make it a prefab.
4. Save and close unity
5. Open the same project on Unity 2019.1.0a9

Actual Result
Prefab assets appear in cyan color, Select Two Column layout from Project tab for better visualization

Expected Result:
Prefab assets should be in the same color even after upgrading projects

Reproducible on:
2019.1.0a9

Working fine on:
2019.1.0a8, 2018.3.0b10, 2018.2.0f2

Environment:
Windows and Mac

Note:
1. After creating a new project or upgrading a project, Editor appears in cyan color for fraction of seconds at the start.
2. Works fine when project is upgraded from 2019.1.0a7 to 2019.1.0a8
3. Works fine when project is upgraded from 2019.1.0a8 to 2019.1.0a9