Reported by a user in production, see RT 247077

In the case reported by the user, entries from one day in January of this year had been included in the guestbook response download but no longer are. I've confirmed they are still in the db and using the same guestbook id.

I do not immediately know what might cause this but wanted to report it for further investigation. One thought might be to reproduce in a test environment, enable db debug output and reproduce the issue. We then compare that query which misses the entry with the one we run manually to see what's different.