I was having a similar but not identical issue, the solution I found might apply to you as well, who knows?
So, my team and I start writing devlogs long before they go live and we keep them saved as drafts. I published a log yesterday and started drafting one today, which is when the one we published disappeared from the game's page.
I fiddled around and discovered the issue. It turns out that the drafts we keep saved were, one by one, reducing the number of devlogs that show up on the page. When it got to 8 drafts that pushed off the last one and no devlogs at all were showing up. I deleted a few old drafts and that solved the issue for us.