Hello,
We fixed our price filter and now it works in the same way as the default one. But we found that the default filter does not work very well as you mentioned in the latest message. We enabled the default theme – Storefront – and there is the same price range https://gyazo.com/15168d4aace4a3f34a6d2bdacd3dc2dd
If default WooCommerce widget with default WooCommerce theme displays incorrect price range we can do nothing with this. Contact WooCommerce plugin support to find out what is the reason of this.
Regards