Uniform scaling in the viewport not working as expected when additive mode is enabled

The uniform scaling does not work as expected
Repro Steps:
1) Add a cube to a level
2) Set the scale (X = 16, Y=9, Z=9)
3) Click the Lock icon to activate the Uniform Scale feature
4) In the viewport using the scaling mode gizmo, scale the object. The target Scale I used was scaling down X = 8.

The expected outcome is for the Y to equal 4.5 and Z to also =4.5, but the relative scale that uniform scaling gives does not work properly. You can type the values into the scale parameters in the Details panel, which does work as expected.