Shopify - Colour Filter not working on the store

On the collection page, on the filter option, when selecting a colour from the "Colour" options, the filter doesn't work and is not presenting that colour result, for example when selected "orange", no filtering will take place and the collection pages remains exactly as before. We are using the Shopify "Discovery and filter" app, and we are on a 2.0 theme Empire. The other filters are working as expected, it is only when selecting the colour option.