Widget animations queued before Slate creation are not carried out in UE5.8

We are currently upgrading some of our systems from Unreal 5.6 to Unreal 5.8, and we've noticed an issue with Widget animations. In one of our commonly used actors, a Widget animation is queued in the actor's BeginPlay using QueuePlayAnimation (representing a monitor being switched on). In Unreal 5.6, once the Slate for this widget has been constructed, the animation plays out, and the actor behaves correctly. Unfortunately under Unreal 5.8 this does not happen - the queued animation is being dropped and never plays, meaning that the actor behaves incorrectly.

Steps to Reproduce

• Open SlateAnimationRepro project in Unreal 5.6.
• Start playing in level ReproLevel
• Fly the camera backwards and forwards, and note that as the actors are streamed in, they play an animation going from a black rectangle to a green rectangle.
• Open SlateAnimationRepro project in Unreal 5.6.
• Start playing in level ReproLevel
• Fly the camera backwards and forwards, and note that as the actors are streamed in, they no longer play an animation and remain as black rectangles.