False positive duplicate queries

Plugin is identifying duplicate queries where it shouldn’t. I cached function output using static like this

if ( ! is_null( $cache ) && array_key_exists( $vendor_id, $cache ) ) {
	$sold_by = $cache[ $vendor_id ];
} else {
	$sold_by = $cache[ $vendor_id ] = wcv_get_sold_by_link( $vendor_id );
}

checked with xDebug to be sure and else statement is executed only twice although QM is reporting

WCV_Vendors::get_vendor_shop_page()
24 calls
WCV_Vendors::get_vendor_shop_name()
24 calls

and

WCV_Vendors::get_vendor_shop_page()
5 calls
WCV_Vendors::get_vendor_shop_name()
5 calls

those methods are descendent in call stack of cached wcv_get_sold_by_link() function