Posted by: @jeanne

Is there a setting in wpforo that sets the order of posts for various user groups?

There is no such feature in wpForo. Make sure you don't have custom code for wpForo in your active theme functions.php file. This could be affection of some custom code. But the cache affection is still actual, you never know how the cache makes tons of problems, so this still the first problem maker.

Thank-you, @Robert, will research the cache issue further.