Why can people reply, but not see their reply to a forum post from a moderated person?

We are an open community so allow our IET Members to bypass moderation, but we moderate everyone else. My question here is about the journey for the moderated posts. For example, a non-IET member will create a community account and post to the forum. That post goes to the moderators for review. We approve the post, but we're not convinced the person is genuine so they remain in the moderated state. Their post is visible in the forum and other (un-moderated) community members are able to reply. However, because the OP is in a moderated state, all replies also go into the moderation queue - is that expected behaviour, or have we missed a setting somewhere?

If we don't get to approve the replies quick enough, we've found it confuses the people who have written them and they think something has gone wrong.

Does that make sense? Does anyone else have this problem?