Would be kind of griefing if I took your post / topic and “replied as new topic” 15 times, and you were forced to track all those new topics.
So this is by design from my perspective.
You are always notified that someone “replied as new topic” to your post (this feature is relatively new), and that should suffice for guidance to check out the new topic, read it (which can infer tracking if over 4 minutes of reading), or reply to it (which infers tracking), or otherwise manually set notifications on it.