The problem was fixed when I changed woocommerce sku search plugin as follows
This is what didn’t work: “Search By SKU – for Woocommerce” AT https://wordpress.org/plugins/search-by-sku-for-woocommerce/
This is what did work: Ajax-search-for-woocommerce at https://wordpress.org/plugins/ajax-search-for-woocommerce/
This Ajax search uses autocomplete and launches a Gorgeous product listing preview and image popup right from the main menu or a widget or shortcode!
