A very minor issue we have noticed on our self-hosted Discourse (v1.8.0.beta5 +33) - the issue described in the following topic is still occurring for us (posts that have been split are appearing as not having being visited):
It doesn’t always behave this way. A topic that I split would not appear “grayed” out to me (an Admin), but it did to another Admin. Moderators have reported the same thing.
The only difference that I can think of between the two split topics - apart from the different dates - is that the working split topic had only one post selected whereas the topic with this bug had two posts selected to create the new topic.