Which is exactly one of the cases for why I don’t think Discourse should remove all traces. It should still at least show that little indicator in the corner for who they replied to, and have it link back to the post they replied to, even if that link just scrolls the thread.
I get the desire to remove quoted material, but not removing any indication of who was replied to. It encourages using the reply feature in an unintended manner like this, as the user sees no difference in the post that clicked the global reply button and one which replied to a specific post.
There’s also the obvious exploit of replying to someone using the global reply button, so they don’t get a notification, while everyone in the thread believes they did.
It seems a relatively easy fix to just use the existing UI to show that the post was a reply to the previous post, not to the full thread. There are just so many ways not distinguishing the two can and has caused confusion.
I really wish @codinghorror would look into fixing this.