To Reproduce:

1. Import the attached packagae 'repro.unitypackage' & and add 'CurveTest' prefab to the scene.

2. Make sure that the curve in 'Test Curve' only contains a single key and that it's value is not 5f.

3. Click 'Evaluate', observe that transforms position was not updated even if the curve in the clip has a key, and returns 5f, when evaluated (using AnimationUtility).

4. Add an additional key, 'gameObject.SampleAnimation' works fine, even if the first key is in the same place and the time argument hasn't been changed.