I hope
Hasann come a proper fix to this hack!
I have tried to make my own fix, that removes one of the 2 Invitation System bloks in the UserCP
I have made a new "product-invitation.xml" that should fix the problem!
It works on my forum!

I have added the new "product-invitation.xml" to this post.
Hope you can use this fix!
I'm not a coder - use this on you own risk!