使用add_rewrite_endpoint传递MULTIPLE变量失败

Question

I have read many tutorials about passing multiple variables to a post/page in wordpress, using add_rewrite_endpoint. I am currently passing 2 variables, calendar_year / calendar_month . It works good for both but separately each one. Using both like (http://myserver/mysite/availability/calendar_year/2016/calendar_month/10/) only gets the year and if I pass them on reverse, only gets the month. Availability page shows correct (No 404 error), but it fails taking the last parameter when there are the two of them. Here is my code for add_rewrite_endpoint

function booking_calendar_add_endpoints() {
    add_rewrite_endpoint('calendar_year', EP_ALL);
    add_rewrite_endpoint('calendar_month', EP_ALL);
}
add_action('init','booking_calendar_add_endpoints');

And this is how I get it and use it:

global $wp_query;
$year_var = $wp_query->get( 'calendar_year' );
$month_var = $wp_query->get( 'calendar_month' );

I am sure I am missing something. Does anyone have a solution for it? Thanks.