I have problems too. My page isn´t showing correctly since the update. Please have a look at it. I clicked the button for the css update and updated the addons
wpForo Advanced Attachments and wpForo Embed.
How about this:
Please help me fast because the page is live!
I think we found the design crashing problem maker. This issue only exists if you enabled the "Turn WordPress to wpForo" option in Forums > Settings > General Tab. So just confirm that all you use the same option. We're preparing the update, you don't need to disable that option.