在我们开始之前，您应该正确地缩进代码并删除php垃圾邮件。这使您的代码更易于阅读和理解。其次，使用卷发（{}）而不是语法:, endif 和endwhile. 它更易于调试和阅读。另一个提示是，注释代码以备将来参考，这样可以更容易地记住您在一个月或一年前所做的事情

你的代码应该是这样的

<?php
    $today = date("Y-m-d");             
    $argsmi = array(
        \'posts_per_page\' => 1, 
        \'post_type\'      => \'imprezy\', 
        \'orderby\'        => \'meta_value_num\', 
        \'order\'          => ASC, 
        \'meta_query\'     => array(
            \'relation\'   => \'OR\',
            array(
                \'key\'     => \'data_imprezy\',
                \'value\'   => $today,
                \'compare\' => \'>=\',
                \'type\'    => \'datetime\'
            ),
            array(
                \'key\'      => \'data_imprezy_do\',
                \'value\'    => $today,
                \'compare\'  => \'>=\',
                \'type\'     => \'datetime\'
            )
        )  
    );

    $temp = $wp_query;
    $wp_query = null;
    $wp_query = new WP_Query( $argsmi );
    if ( $wp_query->have_posts() ) { 

        while( $wp_query->have_posts() ) { 
        $wp_query->the_post(); ?>

            <div class="singleevthumbdiv">

                <a href="<?php the_permalink(); ?>">

                    <?php
                    if ( has_post_thumbnail() ) {

                        the_post_thumbnail(\'thumbnail\', array(\'class\' => \'singleevthumb\'));

                    }
                    ?>

                </a>
                <div class="cbmob"></div>

                <div class="datatitle">

                    <a href="<?php the_permalink(); ?>" class="singleevtitle"><?php the_titlesmall(\'\', \'...\', true, \'25\') ?></a><div style="clear:both;"></div>

                    <?php 
                        $date = DateTime::createFromFormat(\'Ymd\', get_field(\'data_imprezy\')); 

                        $datedo = DateTime::createFromFormat(\'Ymd\', get_field(\'data_imprezy_do\')); 
                    ?>

                    <span class="data">

                        <?php 
                            echo $date->format(\'d-m-Y\'); 

                            if( get_field(\'data_imprezy_do\') ){

                                echo \'- \' . $datedo->format(\'d-m-Y\');

                            } 
                        ?>

                    </span> 

                    <div style="clear:both;"></div>

                </div>

            </div>

        <?php 
        }                                              

        $wp_query = null; 
        $wp_query = $temp; 
        wp_reset_query(); 

    }
?> 

要解决您的问题，请使用$wp_query 哈克很脏，我真的不喜欢。您永远不应该弄乱全局值，因为这会在为全局值设置外部值时破坏全局值。即使您稍后重置了该值，这仍然是一个肮脏的黑客行为。这是一样的什么query_posts 是你永远不应该使用的

您应该在全局范围变量之外使用自定义变量。

基于以上内容，您的代码应该如下所示

<?php
    $today = date("Y-m-d");             
    $argsmi = array(
        \'posts_per_page\' => 1, 
        \'post_type\'      => \'imprezy\', 
        \'orderby\'        => \'meta_value_num\', 
        \'order\'          => ASC, 
        \'meta_query\'     => array(
            \'relation\'   => \'OR\',
            array(
                \'key\'     => \'data_imprezy\',
                \'value\'   => $today,
                \'compare\' => \'>=\',
                \'type\'    => \'datetime\'
            ),
            array(
                \'key\'      => \'data_imprezy_do\',
                \'value\'    => $today,
                \'compare\'  => \'>=\',
                \'type\'     => \'datetime\'
            )
        )  
    );

    $q = new WP_Query( $argsmi );
    if ( $q->have_posts() ) { 

        while( $q->have_posts() ) { 
        $q->the_post(); ?>

            <div class="singleevthumbdiv">

                <a href="<?php the_permalink(); ?>">

                    <?php
                    if ( has_post_thumbnail() ) {

                        the_post_thumbnail(\'thumbnail\', array(\'class\' => \'singleevthumb\'));

                    }
                    ?>

                </a>
                <div class="cbmob"></div>

                <div class="datatitle">

                    <a href="<?php the_permalink(); ?>" class="singleevtitle"><?php the_titlesmall(\'\', \'...\', true, \'25\') ?></a><div style="clear:both;"></div>

                    <?php 
                        $date = DateTime::createFromFormat(\'Ymd\', get_field(\'data_imprezy\')); 

                        $datedo = DateTime::createFromFormat(\'Ymd\', get_field(\'data_imprezy_do\')); 
                    ?>

                    <span class="data">

                        <?php 
                            echo $date->format(\'d-m-Y\'); 

                            if( get_field(\'data_imprezy_do\') ){

                                echo \'- \' . $datedo->format(\'d-m-Y\');

                            } 
                        ?>

                    </span> 

                    <div style="clear:both;"></div>

                </div>

            </div>

        <?php 
        } //endwhile                                              

        wp_reset_postdata(); 

    } //endif
?>