Hmm, I think this is an issue with the default Lemmy UI only. The API has all three post, it displays correctly on the other apps I tried, and it's federating out correctly: https://piefed.ca/c/wwater@lemmy.ca

I suspect this is because the default Lemmy UI does not render "duplicate" posts when they appear on the same page, and instead places them as "crosspost" links on the oldest post. If you go to !wwater@lemmy.ca and look the entry for your Oct 28th post, there is a "cross-posted to: wwater" note on it with a link to the missing post.

I will need to look into if this is intended behaviour or a bug. In the meantime, you can likely fix this by making each post unique. I see that wwater.ca/example redirects back to wwater.ca nicely. So you could edit the Nov 4 posts to wwater.ca/2026-11-04 and the Lemmy UI should treat it as a unique post.