1. What happened
After applying Optimal anim compression, I lose all animation after 1 second.

2. How we can reproduce it using the example you attached
Open attached scene or animation with more than 1 sec of animation
Select the Kicks motion
In the Inspector, Anim.Compresion, choose Keyframe Reduction = animation plays completely.
In the Inspector, Anim.Compresion, choose Optimal = animation plays until ~1 sec., then nothing... :(

note: This issues seams to only be with the FBX since selecting and looking at the produced "clip", the animation look fine.