new_em_get_event_shortcode

<?php
    // this caused the issue
    function new_em_get_event_shortcode( $atts, $format = '' ) {
        global $EM_Event, $post;
        $return         = '';
        $the_event      = is_object( $EM_Event ) ? clone( $EM_Event ) : null; // save global temporarily
        $atts           = (array) $atts;
        $atts['format'] = ( $format != '' || empty( $atts['format'] ) ) ? $format : $atts['format'];
        $atts['format'] = html_entity_decode( $atts['format'] ); // shorcode doesn't accept html
        if ( ! empty( $atts['event'] ) && is_numeric( $atts['event'] ) ) {
            $EM_Event = em_get_event( $atts['event'] );
            $return   = ( ! empty( $atts['format'] ) ) ? $EM_Event->output( $atts['format'] ) : $EM_Event->output_single();
        } elseif ( ! empty( $atts['post_id'] ) && is_numeric( $atts['post_id'] ) ) {
            $EM_Event = em_get_event( $atts['post_id'], 'post_id' );
            $return   = ( ! empty( $atts['format'] ) ) ? $EM_Event->output( $atts['format'] ) : $EM_Event->output_single();
        }
        // no specific event or post id supplied, check globals
        if ( ! empty( $EM_Event ) ) {
            $return = ( ! empty( $atts['format'] ) ) ? $EM_Event->output( $atts['format'] ) : $EM_Event->output_single();
        } elseif ( $post->post_type == EM_POST_TYPE_EVENT ) {
            $EM_Event = em_get_event( $post->ID, 'post_id' );
            $return   = ( ! empty( $atts['format'] ) ) ? $EM_Event->output( $atts['format'] ) : $EM_Event->output_single();
        }
        $EM_Event = is_object( $the_event ) ? $the_event : $EM_Event; //reset global

        return do_shortcode( $return );
    }
    add_shortcode( 'event', 'new_em_get_event_shortcode' );

    // this fixed the issue
    function new_em_get_event_shortcode( $atts, $format = '' ) {
        global $post;
        $return           = '';
        $atts             = (array) $atts;
        $atts[ 'format' ] = ( $format != '' || empty( $atts[ 'format' ] ) ) ? $format : $atts[ 'format' ];
        $atts[ 'format' ] = html_entity_decode( $atts[ 'format' ] ); //shorcode doesn't accept html
        if ( ! empty( $atts[ 'event' ] ) && is_numeric( $atts[ 'event' ] ) ) {
            $EM_Event = em_get_event( $atts[ 'event' ] );
            $return   = ( ! empty( $atts[ 'format' ] ) ) ? $EM_Event->output( $atts[ 'format' ] ) : $EM_Event->output_single();
        } elseif ( ! empty( $atts[ 'post_id' ] ) && is_numeric( $atts[ 'post_id' ] ) ) {
            $EM_Event = em_get_event( $atts[ 'post_id' ], 'post_id' );
            $return   = ( ! empty( $atts[ 'format' ] ) ) ? $EM_Event->output( $atts[ 'format' ] ) : $EM_Event->output_single();
        }
        //no specific event or post id supplied, check globals
        if ( ! empty( $EM_Event ) ) {
            $return = ( ! empty( $atts[ 'format' ] ) ) ? $EM_Event->output( $atts[ 'format' ] ) : $EM_Event->output_single();
        } elseif ( $post->post_type == EM_POST_TYPE_EVENT ) {
            $EM_Event = em_get_event( $post->ID, 'post_id' );
            $return   = ( ! empty( $atts[ 'format' ] ) ) ? $EM_Event->output( $atts[ 'format' ] ) : $EM_Event->output_single();
        }

        return do_shortcode( $return );
    }
    add_shortcode( 'event', 'new_em_get_event_shortcode' );