When getting values for anything other than a post you must supply the correct $post_id value to ACF so it knows where to get the value from. For terms it is explained here https://www.advancedcustomfields.com/resources/adding-fields-taxonomy-term/ and all of the different values that might be needed are explained in the get_field() documentation here https://www.advancedcustomfields.com/resources/get_field/
