The child of an animation blueprint is not properly recompiled when the it's parent is compiled.
Found in 4.24.1 CL#10757647
1. Create a new animation blueprint that inherits from ThirdPerson_AnimBP.
2. Open ThirdPersonCharacter and set the Mesh to use the new AnimBP.
3. Launch the game and notice everything works fine.
4. Close the game.
5. Open ThirdPerson_AnimBP and compile it manually.
6. Launch the game and notice the character is T-Posing.
7. Close the game.
8. Open your new AnimBP and compile it manually.
9. Launch the game and notice everything works fine.
Result: Compiling the parent anim blueprint doesn't break child anim blueprints.
Expected: The child anim blueprint works as expected.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-86356 in the post.