Hello,
We’ll fix it in next theme update. To fix it now find in xstoreframework/theme-functions.php file
etheme_ajax_search_action() function http://prntscr.com/j22ny9
Find $_product = wc_get_product( get_the_ID() );
replace by
global $woocommerce;
$_product = new WC_Product( get_the_ID() );
Regards