This looks like a caching issue, similar (if not identical) to #746, #769. With #769, this was caused (or perhaps simply fixed) by a lack of a restart of the celery service, which does the cache invalidation after page save.
Editing the page in question did not result in a cache refresh, as per report above. Restarting the celery service (service celery restart) followed by editing the page resulted in a cache refresh. My current hypothesis is that a fab deploy was done and the celery service wasn't restarted at some point.
Looking at the celery log at /var/log/celery doesn't show anything illuminating about cache invalidation.
fab deploy is restarting the celery service, so I'm not immediately sure why a manual restart fixes the problem. Perhaps it's the sitemaps code crashing celery, so I'll take a look at that now.
Notes from before:
This looks like a caching issue, similar (if not identical) to #746, #769. With #769, this was caused (or perhaps simply fixed) by a lack of a restart of the celery service, which does the cache invalidation after page save.
fab deployis restarting the celery service, so I'm not immediately sure why a manual restart fixes the problem. Perhaps it's the sitemaps code crashing celery, so I'll take a look at that now.