Sarasa fonts from .ttc container not working

[ei-grad]

Under ArchLinux with installed ttf-sarasa-gothic package, the following config:

[fonts]
size = 11
family = "Sarasa Term Slab CL"

Results in following font rendering:

If I extract Sarasa Term Slab CL font variants into separate ".ttf" files and remove ttf-sarasa-gothic package, then it renders normally:

Files of ttf-sarasa-gothic:

→ pacman -Ql ttf-sarasa-gothic | grep ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-Bold.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-BoldItalic.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-ExtraLight.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-ExtraLightItalic.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-Italic.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-Light.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-LightItalic.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-Regular.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-SemiBold.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-SemiBoldItalic.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-Bold.ttc
ttf-sarasa-gothic /usr/share/fonts/sarasa-gothic/Sarasa-BoldItalic.ttc