Hello,
XStore theme can’t affect the appearance of the default price filter widget with the default theme if the XStore Core plugin is disabled and if the Storefront theme is enabled.
Probably something happened with the WooCommerce plugin itself (after plugin update or any changes in the plugin settings, not sure).
So, if you need to fix the default widget appearance you need to contact WooCommerce plugin support https://wordpress.org/support/plugin/woocommerce/
So, do you prefer to fix the default widget appearance first and then we’ll take a look at 8theme widget price or you want to fix the 8theme widget appearance the same way as the default widget does and then you will contact WooCommerce support?
Regards