I agree with Michen; I've never had an issue with this either since one clearly says "Adult" in the name of the boards and the other ones does not. I'd rather say that by separating it, that sort of defeats the purpose of having a single list to display all unread posts/replies.
I think a better approach might be to have a filter where you can keep it disabled to display everything in one list (same as it is right now or enable to filter it by section (TFF Central, Furry Chat, etc.) and perhaps also by board. This could perhaps also allow you to hide certain threads you have little interest in by default to make the list even shorter and more focused on threads you have a higher chance of wanting to read.