Hi again,
Yes, this is in Play mode and when you lose and regain focus, there's no need to select the SkeletonGraphic, it happens at the moment of the focus regain. With this file (that I'll send to you now) only happens with one animation, but it's also the only animation that hides/shows an attachment. We don't have any other skeleton that does that.
I can't think on a third-party plugin that could affect on this.
As I said, I'll send to you this exact exported Spine file.
(Our artist is super happy with that, thank you!!!)