Starting yesterday, I've started to notice that the home page sometimes doesn't update, even though the actual WordPress page does. Last night, it took nearly half an hour for an article that I'd published to show up on the home page. As I write, the home page currently does not display the latest article that I've written.
On the other hand, it doesn't occur all the time. When I published two other articles earlier in the day, both of them showed up on the home page just fine.
This has never occurred in the past. To give some clues on any potential sources of the problem, yesterday I had to change a couple of chmod permissions in order to complete reinstallations of a couple of plugins which had failed to update properly when using the internal WordPress plugin tool. To complete these tasks, I temporarily set my domain's .htaccess file to 755 and the WordPress directory to 777 (non-recursive), in accordance with instructions. After reinstalling the plugins, I then changed these back to what they were: 644 and 755 respectively.