How to reproduce:
1. Download attached project file and open "test" Scene
2. Enter Play Mode and select GameObject in Hierarchy Window
3. In Inspector Window edit Delayed property and unfocus field away

Actual result: Delayed fields revert back to their previous value when you tab out of the field
Expected result: Delayed field should not return a new value until the user has pressed enter or focus is moved away from the field

Reproduced with: 2017.1.2f1, 2017.2.0f2, 2017.3.0b4
Not reproduced with: 5.6.4f1, 2017.1.1f1

Regression since: 2017.1.1p3

Note: New value works if user has press enter