Animation poses can be "cached" by reroute nodes as an output in

by design, animation pose output pins can only connect to a single pose input pin. However, you can circumvent this behavior by dragging off the initial pose node output pin into an empty spot on the graph and choose 'Add Reroute Node...' then, you can drag off the reroute node into another pose input pin.

1. Open a new Third Person Blueprint Template project.
2. Navigate to the Mannequin->Animations folder.
3. Open ThirdPerson_AnimBP
4. Drag in ThirdPersonJump_Start Animation Asset into the Anim Graph
5. Create a Blend Node
6. Drag off of ThirdPersonJump_Start-> Add a re-route node.
7. Plug in the reroute node into both A and B Inputs of the blend space.

Result: Successful blend of two poses via re-route node 

Expected:  Unable to use a single pose to blend via re-route node