Comment 12 for bug 1992369

Looking into this again, I found that I had the following line in /etc/environment:

FREETYPE_PROPERTIES="truetype:interpreter-version=35 cff:no-stem-darkening=1 autofitter:warping=1"

I can't remember why I set this, probably some hinting issues in an old Xubuntu version.
Removing it causes v40 of the interpreter to be used, fixing the broken letters.

The font is obviously broken when used with v35, but few people are going to notice unless they're as clumsy as me, so you may want to close the ticket.

I also found out that `ftview` from the freetype2-demos package is great for investigating these issues, as it lets you cycle through all the relevant settings.

Thanks for your help and apologies for not realising that I had a non-standard setup.