Hi ! Hello everybody, I'm new here.
I ve got exactly the same problem on KODI 18.9 (adaptation by PATRICK) installed on an Asustor NAS. Sometimes (only sometimes !), font totally disapearing while reading a movie. Impossible to read any menu after, font totally disapear !
Same problem if I'm on an original KODI just afer installation or with Andromeda Skin v2 using OpenSans font.
Only way is to restart KODI.