This is expected. mannequines are not real users and this is just a placeholder. If you’re seeing that something is authored by mannequine, this means that the content is not claimed by the specified github user.
The corresponding GitHub user decided not to accept invitations to claim this content on github and we are not allowed to “force attribute” it.
I believe that it does remain possible for a mannequin user to accept the invitation to join the llvm-bz-contributors group, in which case they can re-associate those “mannequin” bugs with their account. (I’m not sure the full set of steps that needs to be taken for this to occur, however).