That lists includes /usr/X11R6/lib/X11/fonts, we should probably just don't monitor non existing directories (that means that if they get created the system is not going to pick them up, but that seems unlikely to happen anyway, or not frequently enough that it would be an important issue)
The issue is coming from the xsettings code, it has a loop doing
" while ((str = (const char *) FcStrListNext (list))) {
file = g_file_new_for_path (str);
monitor = g_file_monitor (file, G_FILE_ MONITOR_ NONE, NULL, NULL);
...
"
That lists includes /usr/X11R6/ lib/X11/ fonts, we should probably just don't monitor non existing directories (that means that if they get created the system is not going to pick them up, but that seems unlikely to happen anyway, or not frequently enough that it would be an important issue)