Variation swatches on works only for some products on archive pages

I’m developing a WooCommerce site using your plugin to only colour options for t shirts and hoodies which worked perfectly and now any new products that added won’t allow image swapping on the product pages when clicking on the colour swatches.

It was working until your latest update BTW and all settings and variations are the same for products when one will work and another refuses to change the thumbnail in the Woo loop to the variation image.

I hope this makes sense

Thank you