In my forum, people have real names with all different kind of accents. I tried to use the username completition launched by typing
@ to mention a user while writing a response and found that I could not find users by their name if the name contains an
You can test it on your own. Try to find @zogstrip by typing
@ followed by
Ré for Régis. The actual username lookup is
https://meta.discourse.org/u/search/users?term=r&topic_id=65888&include_groups=true. Note that all characters from the e with accent on are stripped off from the search query.