Discourse by default doesn’t indicate that a post is a reply to another if the replied-to post is directly above it. This is bananas behavior and not how any other reply mechanism in the multiverse works, so it often confuses users into deleting their posts and redoing them because they think they clicked the wrong reply button or that the forum is bugged because the reply button on the post and the thread behave identically.
I’d suggest toggling this behavior in the Discourse settings, the option should be called “suppress reply directly below” and is turned on by default. Turning it off makes replies to posts always look like replies no matter where they are. Replies to the thread are unaffected, it doesn’t turn every post into a reply.
For reference of people smacking into this, see this or this or this.
