Tooltips are missing for "Apply" and "Revert" buttons in the Override window, refer attached screenshot

Steps to repro:
1. Create a new project
2. Hierarchy > Create > 3D Object > Cube
3. Make a prefab of Cube
4. Hierarchy> Cube > Inspector > Scale X = 5
5. Override > Transform > Override window > Hover mouse Apply and Revert buttons

Actual Result:
Tooltips are missing for "Apply" and "Revert" buttons

Expected Result:
Tooltip appears when the mouse hovers on the Apply" and "Revert" buttons

Occurring on:
2020.2.0a17, 2020.1.0b15, 2019.3.15f1, 2019.2.13f1, 2019.1.11f1, 2018.4.24f1

Environment:
Occurring on Windows 10 & Mac 10.15.