Hi Majid,
The issue seems to be with the URL encoding – when I click on the switch button, it removes encoded URI components, such as empty whitespaces like ” ” or other characters as well.
You can try this even with the native search, for example searching “far mu”, results in this URL (replace yoursite.com with your site domain): https://www.yoursite.com/?post_type=product&s=far%20mu
When clicking on the sorting, it removes the “%20” whitespace character and changes the phrase to “farmu” which is incorrect: https://i.imgur.com/O3vh4R6.png
See after: https://i.imgur.com/y1hkKZz.png
Unfortunately that section is unrelated to the plugin, so it needs to be corrected elswhere.