The topic doesn’t show up in my “unread” list, but it doesn’t get the “read” styling in the list – that is, its title is still displayed in black, rather than the expected light grey. It’s not a major issue, but it does make the inbox-zero perfectionist in me twitch.
There are a heck of a lot of improvements we still need to make on split topics, for example, the split topic should properly be marked read if the posts in it were already read pre-split…