Hmm. I see wpForo asks in reg form for name and for 'display name publicly as' which is correctly present in system/plugin email.
If you see that on wpForo form it doesn't mean this is wpForo fields. wpForo registration form is the WordPress form a little bit re designed. This form has tons of functions which allows other plugins and codes insert own fields in this form. And the result you see. This is the WordPress theme fields or inserted by other plugins. PLEASE DEACTIVATE ALL PLUGINS AND CHECK IT AGAIN. If it doesn't removed field, then change the theme and check. This maybe theme code.
@Robert You are right. I disabled WP Spamshield ( https://www.redsandmarketing.com/plugins/wp-spamshield/) and the extra fields went away. I can disable spam shield for reg forms but that is not a good idea. It is the best ever security anti spam plugin. I always delete the heavy Akismet and just use this without a need ever for recaptchas/captchas or bothersome plugins of this type and never a single spam gets through. I love this plugin. Used to be free but I got the extended license for all my sites on codecanyon and only use this to protect GF and comments, WC, reg etc etc.
I contacted the developer but perhaps also on your end something can be done for compatibility?
Thank you in advance and hope all my issues make your plugin even more awesome!
I'm sorry but we can't make it compatible with wpForo. We don't know how it works. It's easier and more correct to make the Spamshield functions compatible with wpForo registration form. This should be done by Spamshield developers. wpForo Reg form is the same WP reg form. We don't have any specific things here.
Aslo I think they should have options to remove the extra fields. These are not required. Try to remove those fields and test it again.
Maybe you should try The Shield for your security, spam and many other things. I haven't found anything better and lighter yet.