Triggered by the above little incident, I wonder if split-into-new-topic links (i.e. the link back to the original topic) could not somehow be visually distinguished from “ordinary” link-backs, e.g. with a different or additional icon. The same would make sense for links generated by reply-as-new-topic.
A more generic way of putting this is to say: why not distinguish different types of link back?
I am not entirely convinced that this would improve the UX as it’s really a matter of trying it out, but my reasoning is that different link-backs have different meanings/functions and distinguishing them might provide useful cues for better orientation. It might actually suffice to distinguish link-backs that somehow originate from the same topic (via splits or replies) and those that don’t.
To use the example referenced above: the “incident” may have been avoided if it had been more obvious from the start that the OP is a split from another topic. (I’m assuming that most users don’t routinely pay much attention to the link-backs under a post but might want to be alerted to the kind of links discussed here.)