CineCameraActor ActorToTrack property cannot be set to a spawnable actor

In the repro, the first selection is not spanable, but the ActorToTrack is set correctly at this time. When trying to select a spawnable actor, it cannot set it to ActorToTrack. 

When using the eyedropper tool, an error message appears "Unloaded reference to Actor ID '{Actor}', use Browse to pin actor". 

1. Create a new sequencer track
2. Place CineCameraActor in level viewport
3. Drag and drop a CineCameraActor into the level sequence
4. Place Cube on Level
5. Register the Cube in the sequencer by drag-and-drop and select "ConvertToSpawnable"
6. Select CineCameraActor property and try to register Cube to ActorToTrack

Cube cannot be registered in ActorToTrack. Cube is not listed in the details panel list of ActorToTrack. When select a Cube using the eyedropper tool, the link is broken after PIE.