Static page cutting off

I’ve a problem with this static page:

https://dreamflesh.com/journal/one/

It seems I’ve reached some mysterious character limit. Whenever I add another paragraph somewhere, nothing after the last bit of page content gets output. All the content’s there, but the WordPress ‘Edit page’ link and everything after (including the whole of the sidebar) isn’t sent to the browser.

I’d love to induce the error so you can see exactly what I mean, but I’ve just launched this labour-of-love journal, and it’s just got a mention on a high-traffic blog, so I’m loathe to break the page just now!

I just wondered if this rang any bells with anyone here.

I have static pages much longer than this on the site without this issue, which makes it even more confusing…