I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book; and if anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life and from the holy city, which are written in this book.
— Revelation 22:18-19
A mistranslated text is not the same as an adding or taking away of Christ's Words.
But to say it's been mistranslated, you are using a particular standard of a particular text or translation.
What version of the Bible are you using?
Or are you using the actual Herbrew and Greek texts manuscripts?
This video might give you insight.
RE: Is There Punishment For Those Who Mistranslated The Bible?