I am getting the following error on my current theme:
Uncaught TypeError: $(...).suggest is not a function
You are minifying/compressing the forum pages. Disable ANY optimizer or caching for the page you have the wpforo Shortcode.
On the other topic you posted (add topic) you replied that you do not have a caching plugin but you do have an optimizer.
All those problems apparently come from that.
btw: your forums looks super slow for some reason.