Outside of AnimBP's, Animation Sequences with negative Rate Scales do not animate

Animation Sequences with negative Rate Scales do not play outside of using them in Animation Blueprints...unless they are looping.

UPDATE: A negative rate scale value also breaks Anim Montages. https://answers.unrealengine.com/questions/196510/unable-to-create-a-valid-montage-using-an-animatio.html

1. Create a new Third Person Project
2. Find the running animation and create a duplicate
3. Open the duplicate
4. In the Anim Asset Details, change the Rate Scale to a negative value (I used -0.1 so that it'd be easier to see without looping)
5. Create an instance of the Skeletal Mesh actor in the level
6. In the actor's details, change the animation mode to "Use Animation Asset"
7. Select the duplicated animation that you created from the dropdown
8. Disable Looping
9. PIE

Result: Animation doesn't play. Enable looping and it will play. The same occurs if add this skeletal mesh to a Blueprint and use a "Play Animation" node.