Value modifiers need to be entered like this:

How to enter value modifiers correctly: use the exact labels with capitals and spaces, each on one line, without commas.
How to enter value modifiers correctly: use the exact labels with capitals and spaces, each on one line, without commas.

The following things often go wrong:

The values you enter in a facet’s “Value modifiers” field each need to be on a separate line in the form field. Do not put them on one line with commas or add commas to each line.

The values need to match the label (not the slug) of the value exactly, including spaces and capitalization. For example, if you have a category called “Fall Collection”, the value entered in the “Value modifiers” field needs to be exactly that: Fall Collection.

If you have not modified the facet values with output hooks like facetwp_facet_display_value, the quickest way to determine the labels is to look at the facet value labels themselves: the labels beside the checkbox or radio button, or the options in the dropdown. Also make sure to check if capitalization is not changed with CSS, for example with text-transform: lowercase.

In hierarchical facets, if you use “Show only these values”, if you want only specific child terms to show up, you need to include their parent terms (on all levels) too. Or you need to set their parent term ID in the “Parent term” setting. If you use “Exclude these values”, you can directly exclude child terms, without excluding their parent terms.

See also