Custom Blend Graph read only after copy/paste of State Nodes

When copy/pasting a state network, if any transition has Custom Blend Logic, the Custom Blend Graph becomes read only in the pasted version.

1. Start a new project based on the Third Person Template
2. Open the ThirdPersonAnimBlueprint
3. Go to the animGraph and open the State Machine
4. Delete the JumpEnd state
5. Create a transition from JumpLoop to Idle/Run
6. Select the transition and look at the details panel
7. Change the Blend Logic to Custom
8. Scroll down and select Edit Blend Graph
9 Note that it is not Read-Only
10. Select the 3 remaining states (and all the transitions) with a marquee
11. Ctrl+C
12. Ctrl+V
13. Select the pasted transition
14. Select Edit Blend Graph

Result: Custom Blend Graph is read only