The display that shows how many character you have on a realm is not a system that scans all realms to make that determination. It is updated based on logging into the realm itself. Several years ago we did some updates to the system that basically wiped that list. If you hadn’t logged into that realm since, which seems like if it was last played 6-7 years ago, then it wouldn’t normally show up.
Since Ravenholdt was one of the realms that was being connected today, my guess is when that happened it updated the character count list.