Some characters are not being displayed correctly.
The vanilla game has the correct unicode for all the characters but it's not getting the image from the accented.png file, but from the unicode_page_**.png
This does not effect the vanilla game as the unicode files are the same resolution as the accented.png, but this does effect a higher resolution accented.png use in my resource packs.
All the characters display correctly with the ascii.png and nonlatin_european.png, it's just the accented.png file that has some issues.
I always wanted the best quality for the text but I forgot that other players may be playing on older hardware or laptops.
My font was 256px per character which made the accented.png 4604x6912, which is stupidly large and was the thing causing the characters to not display correctly.
In my resource pack I've dropped the resolution in half at no noticeable change in quality, so the font is now 128px per
character and all the characters now display correctly.
So this bug is no longer valid and you may as well close this issue.