I reshared a post from a Mastodon contact. There was a couple of comments from my Hubzilla contacts.
After logging out I noticed the public stream: There was another comment on my post, from a Mastodon user I am not connected to.
I logged in again to check - no such comment.
I double-checked my permissions. I don't allow open comments.
Is this a known problem? I haven't seen it before.