Greetings. I am using Xubuntu 20.04.1 LTS, which comes with FreeType 2.10.1.
As long as I remember, the tilde as diacritic (for example, in ãõñ) is rendered incorrectly in some small font sizes, unfortunately often used. For example, at size 10 the rendering is broken, in these characters, for fonts Cousine, DejaVu Sans Mono, Courier New, Liberation Mono, FreeMono, TeX Gyre Cursor, and Nimbus Mono. I would like to confirm if other users can reproduce the issue. Best regards, packshaud
