Yes sorry I should have shared: It is all in the FAQ
FAQ: How to Format R Markdown Source
There is an option somewhere that show the backticks in this font.
@yihui do you remember what could cause the backtick to be shown this way in LaTeX ?
I know this could happen with quotation mark and smart extension but I can't remember for this case.
Also @startz can you share xfun::session_info("rmarkdown") ? thanks