CMF Filter checkbox not showing checked state

I am using the FS accessible components library for filtering on my site. I have checkbox #4 implemented, which says:
" Style .fs-checkbox_field element active state with .is-active combo class when using CMS Filter."

I have done this on my site, but the active state is not showing up on the live site. Any ideas on what is preventing this from working?

Read only link:

Hey @accounting, the class in your attribute value is different than the one you are showing in your image, can you please try changing the value to is-active and test again?