Repeated Header in a Next.js page using iframe and bbpress

I am new to the tech stack of this issue. I am new to Next.JS and I am new to BBPress. But this is the tech stack of my "WEC MFG" website, https://excellencematter.net. My page.tsx for the interaction menu option has the <iframe> which contains the bbpress functionality.

Now, here is the bug. After a new user account is registered and the new user logs in, the web page is a mess. It looks as if the iframe nests an entire website so that it produces a look where the whole webpage has two navigation bars. I hope I am describing this accurately. Please view the screen shot.

I have done some work with adding "snippets", custom pages and "Additional CSS". But so far the problem has been resistant to my efforts. I need help. I will provide the code you need to detect this bug and solve this problem. Please help.