I so much do not want to dig my tengwar, quenya and sindarin reference material out now
But nevertheless there are cases where misinformation may lead to unwanted corrections.
E.g. I the dwarven inscription on the map in the Hobbit (The one written in futhork) as well as its translation in the book, says: " stand by the grey stone hw
en..." If one happens not to know that it's correct for archaic English - as I didn't - you end up thinking it's a mistake.