Ok thanks - I appreciate you taking the time to help. I'll go back to the Web Builder support with this detail maybe they can help.
Limited Support
Our team is currently on holiday, so support will be limited during this period. Response times may be slower than usual, and some inquiries may be delayed. We appreciate your patience and understanding, and we’ll resume our usual support by the end of August.
@kylew Hi Kyle do you have everything you need now? I've IM you the details requested.
We need you to disable all plugins of your website, except wpForo and PM addon so only wpForo, PM and your builder would be active on the website, and check the PM workability.
After checking the builder, we got that the Builder with default setup doesn't affect on the PM addon. But the issue can be from the builder setup or other plugins + builder or plugins + builders setup, so need to check, do the plugins affect or not.