The bridging message “consider answering the question there” could imply that one should answer only in Slack, whereas it seems preferable to always answer here for posterity. So I’d like to suggest rewording the bridge message to something like this (see emphasis):
Note that the original poster on Slack cannot see your response here on Discourse. Consider transcribing the appropriate answer back to Slack, or pinging the poster here on Discourse so they can follow this thread.
The current message:
Note that the poster on Slack cannot see your response here on Discourse. Consider answering the question there or pinging the poster here on Discourse so they see the response.