Yes, maybe not many notice or care about it for some reason.
As all text in RTL, it’s actually gonna be read “By Author” – so when reading from Right to left, it’s need to be written:
“Author By” <–
Many themes also have an option to remove the “By” altogether – making it even much simpler and cleaner and don’t even need to translate it.
I believe that what most prefer to do anyway.