sorry, there are 300,000 users of bbpress and you have found a couple of instances where users found an issue.
In one advice was to troubleshoot the problem, and the user never came back, in the other one user found that it was a wp mail plugin.
I appreciate that you ae frustrated, but ‘this same exact issue 5 and a half years ago? Is this issue still not fixed?’ is not going to endear you to the free support offered for this free product.
As a first instance, please do the troubleshooting :
it could be a theme or plugin issue
As a test switch to a default theme such as twentytwenty, and see if this fixes.
If that doesn’t work, also deactivate all plugins apart from bbpress and see if this fixes. if it does, re-enable one at a time to see which is causing the error.
If you cannot do this to your site (say because it is live) then use the ‘troubleshooting’ features of this plugin to let you test without affecting other users
Health Check & Troubleshooting
Then come back
Fair point. I will see what I can figure out. Thank you.