Able to Imbue Shiv's Killing Blow with Superior Duration

[moogle]

1. Steps to Reproduce
   1. Enter the Sandbox.
   2. Select Shiv.
   3. Unlock Killing Blow.
   4. Buy Superior Duration.
2. Expected Result
   1. Killing Blow cannot be selected as an imbue-able ability.
3. Actual Result
   1. Killing Blow can be selected.
4. Visual Proof (screenshots, videos, text)
   1. 
5. Severity/Priority
   1. Low/Low
6. Additional Notes
   1. Bloodletting has a duration stat but cannot be imbued. (Might be done purposefully)