Hey Henry, I'm aware of this bug and it will be fixed in the next update. In the meantime, which server are you on so I can give you back your Pokémon?
First things first can you provide proof? We have several people claim they lost a shiny ... so we have to have proof. Can you, in any way shape or form provide a little information. What server where you on before roll back, and what server after roll back. Do you have any eggs (Pokémon that you got from eggs) Where you doing anything in particular. Where you switching servers a bunch? Anything else that can be helpful? Also - message ProfessorHemlock, Aaron, or dmatias7 on Discord. They will be able to further assist you.