Hello,

I have deactivated all the plugins not related to the theme for 5 minutes max and got this result https://prnt.sc/tm602j

As you can see the search by SKU works well. Now I have activated all as they were.

Now you need to deactivate all the plugins not related to the theme, leave these plugins only:

Slider Revolution
WPBakery Page Builder
Woodmart Core
Contact Form 7
MailChimp for WordPress
WooCommerce
Safe SVG

Then activate the plugins one by one checking the search by SKU to detect which one causes the problem.

As soon as you solve the problem with the SKU, please make the full backup of your site and update all the plugins related to the theme and theme: https://xtemos.com/docs/woodmart/update-theme-2/

Best Regards