I have purchased a Character Slot Extension when it was 18/18 available.
After a purchase it became 16/18… I thought I accidentally bought two so I checked on the Character selection but does not seem that way.
I would not end up buying all 18 slots anytime soon… but I thought I would raise it as a bug to see if anyone else experiences this and to hope devs to fix mine.
I also have the same issue as well. I checked with customer support and they said it’s a visual bug. You should be fine but this should be raised to the devs to be fixed among many other things.