How to get missing messages to show in a group forum

I have created a group to test the functionality and created a forum for this group with “Group Forums” as the parent forum. I can create a topic and post messages but after submitting the post the forum will show that the topic and messages exist but the messages don’t appear. The posted topic and reply are visible from the admin interface however.

This problem is unique to groups and doesn’t appear in a sitewide forum. Is this something you’ve seen before?