This bug has existed for quite some time - when a topic is moved from a simplified layout forum the forum home index will show only a topic with more than one post in it as the latest content. With 1.6.2 the problem is even more acute in that even a newly minted single post topic is not shown as the latest content on forum home.
I have this issue too, new posts don't appear on the Last Post Info unless there is a 2nd post added.
I am also experiencing this bug.
Please make sure you don't have cache plugin active on forum page. And leave some screenshot and your forum URL. As you can see it works fine here and you use the same plugin without any change. So I think that's cache issue and that cache is a plugin or Hosting Service cache. You should find an option to remove wpForo forum page from your caches. wpForo has a built-in cache system and you should disable your cache plugins for forum page, but it should be still enabled on other part of your website.
