function.php

/**
 * Filter to modify the returned data from Display Eventbrite
 * to take the day of the start date and apply it to teh end of teh last day  of
 * multi day events
 *
 * So the event appears as a single bookable entry in calendar layouts
 *
 */
add_filter(
	'wfea_api_results', //  hook to filter  returned event data before display
	/**
	 * @param $events
	 * @param $atts
	 *
	 * @return mixed
	 * @throws Exception
	 */
	function ( $events, $atts ) {
		if ( ! in_array(
			$atts['layout'],
			array(
				'cal_list',
				'cal'
			)
		) ) { // only impact cal_list and cal layout
			return $events;  
		}
		foreach ( $events as $key => $event ) {
			$start     = new \DateTime( $event->start->utc );
			$end       = new \DateTime( $event->end->utc );
			$start_day = $start->format( 'Y-m-d' );
			$end_day   = $end->format( 'Y-m-d' );
			if ( $start_day != $end_day ) {
				/**
				 * multiday event found
				 * need to grab end time from end date
				 * and rebuild both local and utc end date/time
				 */
				$start_local                = new \DateTime( $event->start->local );
				$start_day_local            = $start_local->format( 'Y-m-d' );
				$end_local                  = new \DateTime( $event->end->local );
				$end_time                   = $end->format( 'H:i:s' );
				$end_time_local             = $end_local->format( 'H:i:s' );
				$events[ $key ]->end->utc   = $start_day . 'T' . $end_time . 'Z';
				$events[ $key ]->end->local = $start_day_local . 'T' . $end_time_local;
			}
		}

		return $events;
	},
	10,      // priority
	2        // two arguments
);