In some cases I see that the WordPress template is designed from the HTML version. While the designer is both different. How is this done? Will they enter into negotiations with the HTML designer? please guide me. thank you
I think you are talking about author collaboration, you can read more about it here https://help.author.envato.com/hc/en-us/articles/360000471983-Author-Collaborations.
In these cases there are many possibilities why you see this: either for a second account, partners, transfer of rights, joint venture, etc.
And if you decide to do something similar, you should always report it to envato at (AuthorCollaborations).