Steps to reproduce:
1. Open the attached project
2. Open the TestScene scene
3. Play the scene
4. Observe the blue, red and green fields:
The blue 'speed' field updates every second and displays the speed of the character is calculated by taking the difference in positions between updates
The red fields show the value that the method 'apparentSpeed' reports for the run 'AnimationClip' instance that is playing - this corresponds to the inspector value 'Average Velocity' for the clip
The green fields display the value derived from examining 'RootT' first and last keyframes. Once adjusted for human scale, this value appears to match the actual character speed when under root motion control
5. Notice that the red values do not match the observed speed of the character under root motion control

Actual result: The red values do not match the observed speed of the character under root motion control
Expected result: The red values should match the observed speed of the character under root motion control

Reproduced with: 5.5.4p2, 5.6.3f1 , 2017.1.0p3, 2017.2.0b6, 2017.3.0a2