We've received the repro project. I'll check it out.
I think most of the examples in the examples folder are just pretty close to setup pose anyway so they don't reveal that specific problem.
Based on the setup pose of your skeletons, it seems like it's behaving as expected.
In edit mode, SkeletonAnimator GameObjects render whatever is the setup pose of the skeleton.
The setup pose of your skeletons show all the images, so that's what's seen in edit mode.
As I mentioned before, some people were experiencing problems when applying the Animator in edit mode.
That's why that block was there. I can't seem to replicate that old error, but I think the solution here is to just get the default/entry states in the Unity Animator and use that to pose the skeleton in edit mode. What you did is fine too, as long as it doesn't cause you any problems, but it might not the fix we'll apply.