Sure thing. This also took me ages to figure out, but is quite simple in the end…
This is all my reusable element looks like when you first go into it in the editor since the group focus is not visible on page load. It only contains the icon that is initially visible.
Here is what it looks like with group focus visible.
Here is the workflow to show the group focus on click (I do a series of other steps as well when the user clicks on the icon, but the one you are most interested is the first one to show the group focus):
If you still struggle, I suggest trying to get it to work with click. If you can do that, but still struggle with hover then you will know it is a hover-specific issue.