Removing Pose from a Blend by Enum node can cause compile errors when a float is defining all of the blend times.
To skip steps 1-10, download the sample project and open the "BlendByEnumRemoveTest" Animation Blueprint.
1. Start a third person template project
2. Create an Enumeration asset (name it TestEnum)
3. In the Enumeration, add 3 Enumerators and name them
4. Create an animation blueprint based on the mannequin skeleton
5. In the AnimGraph, add a Blend by TestEnum node
6. Right click the node and Add each of the pins that represent the enumerators
7. Create a Float variable and hook it to all of the blend time pins
8. Creat. 3 Play animation nodes and hook them to the poses
9. Hook it all to the Final Animation Pose
11. Right click on the first pose pin and choose remove pin
Result: Compile Errors and Blend Pose Node is broken
Expected: No compile Errors and Node adjusts to the changes
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-21148 in the post.