Cannot bind event dispatchers between two blueprints that share a parent class. This issue also occurs if you use the parent as a variable in the child. The bind event dispatcher seems to only take a self-reference.
1. Open Editor (QA Game)
2. Create blueprint (name it Class_A)
3. In Class_A, create an event dispatcher named "OnDeath"
4. Compile, close blueprint
5. Create two child blueprints based on Class_A (Class_B and Class_C)
6. In one of the child blueprints (Class_C), create a cast to the other (Class_B).
7. From the "As Class_B" output pin, create Bind Event to OnDeath node
Bind Event to OnDeath is created with target of self. Class_B cannot be attached to the target pin.
"As Class_B" pin connects to Target pin on "Bind Event to OnDeath" node.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-19089 in the post.