ChildActorComponent (SkeletalMesh) goes into tpose when calling SetChildActorClass

There is an issue occurring where when updating an animation of a child actor by setting the Child actor class, the animation will flash the skeleton in a T-Pose before continuing with the animation. This issue appears to be a regression

Versions Tested:
4.18.3 CL - 3832480 - Issue does not occur
4.19.0 CL - 3944462 - Issue occurs
4.20.0 CL - 3952118 - Issue occurs

1. Create a new project using the third person template
2. Create an actor blueprint with a ChildActorComponent > Name this "Child_BP"
3. Create an actor blueprint with a SkeletalMeshComponent > Name this "Skeleton_BP"
4. Give this SkeletalMeshComponent an animation ( used the Run animation of the third person template)
5. Set Mesh Component Update Flag for this SkeletalMeshComponent to "Only Tick Pose when Rendered"
6. Call SetChildActorClass on the ChildActorComponent from step #1 and set it's class to the blueprint created in step #2.
7. Set the SetChildActorClass to be used when the "1" key is pressed and set the input of the blueprint to Player 0
8. Add Child_BP tot the level and PIE
9. Press 1 continually
   Result: The Animation attached will quickly T-Pose before going back into the animation
   Expected Result: The animation does not T-Pose