call_user_func_array problem with Vendor Woocommerce Plugin

Hello!

Please I need some help about a special topic. The WordPress warning is exactly this:

call_user_func_array() expects parameter 1 to be a valid callback, class ‘Class->WC_Product_Vendors_Vendor_Frontend’ not found in (…) class-wp-hook.php on line 287

I have touch nothing in my code in reference to the plugin and functions.php. I saw the problem when needed some special fields in vendor’s template and try to do it with ACF. The vendor was not assigned products and the result was “no products found” and all the ACF fields were in their own space. Since here it was all right.
My next step was to assign some products to the vendor and crash! All the fields were dissapeared. I could not believe it!
The web was thinked to be a marketplace and if woocommerce vendor doesn’t work with the special fields I could have some new problems.

I hope it’s easy to solve.
Greatfull so much about your answers.

The page I need help with: [log in to see the link]