为什么我收到错误：PHP警告：高级自定义字段的非法字符串偏移'url'？

Question

I'm using Advanced Custom Fields, and I'm having issues displaying my masthead images. I have a Repeater Field that contains one sub-row "mast-head-images" - which is just an Image field type. In my field settings, I'm pulling the image array, and using that array to grab the URL in my markup. However, I keep getting an error " Illegal string offset 'url'" the same error regarding the alt attribute.

I used print_r and echo to display the value returned, and the correct image URL is being returned. However, the images don't display.

Also, another strange thing, I checked the inspector, and its trying to find 24 images... I only have 3 images I'm trying to add. Where are the other images coming from? Again, all the images don't have a src attribute. What's even weirder, is that some of the image src have random URLs:

    <img src="" alt="" class="carousel-container__img carousel-img-0">
    <img src="h" alt="h" class="carousel-container__img carousel-img-2">
    <img src="1" alt="1" class="carousel-container__img carousel-img-8">
    <img src="i" alt="i" class="carousel-container__img carousel-img-12">
    <img src="2" alt="2" class="carousel-container__img carousel-img-14">

I've made sure that I'm up-to-date and using the latest version of AFC. I don't know if I should change my PHP version? (currently 7.2.1 - I tried reverting back to an older version, but nothing changed.)

I've also deactivated other plugins to test that its not a conflict of plugins - but still nothing.

I've actually hard coded the URLs to rule out anything with the path, and it works perfectly. - my images display. I just need to get it working with AFC, instead.

<header>
<?php  ?>
    <?php 
    $defaults = array (
        'theme_location' => 'main-navigation',
        'menu_class' => 'no-bullet',
        'container' => false
    ); ?>

    <nav class="main-header-nav">
        <img src="<?php echo get_template_directory_uri();?>/icons/Hilton-logo.svg" alt="Hilton Logo" class="header-logo">
        <?php  wp_nav_menu($defaults); ?>
    </nav>


    <?php 

          $topMastHeader = get_field('top_header');
          $bottomMastHeader = get_field('bottom_header');

?>




    <h3 class="header-text tagline">
        <?php echo $topMastHeader; ?>
    </h3>
    <h1 class="header-text">
        <?php echo $bottomMastHeader; ?>
    </h1>



    <div class="cycle-slideshow carousel-container" data-cycle-fx="scrollHorz" data-cycle-timeout="0" data-cycle-prev="#prev" data-cycle-next="#next" data-cycle-caption=".carousel-counter" data-cycle-caption-template="<span class='bigger'>{{slideNum}}/ </span> <span class='smaller'>{{slideCount}}</span>">
        <div class="cycle-caption"></div> 

           <?php  while( have_rows('header_carousel') ): the_row(); 

        // vars
        $mastHeadImages = get_sub_field('mast_head_images');

     ?>     

        <?php  $i = 0;
        foreach( $mastHeadImages as $image ): ?>
            <img src="<?php echo $image['url']; ?>" alt="<?php echo $image['alt']; ?>" class="carousel-container__img carousel-img-<?php echo $i; ?>" />
        <?php $i++; endforeach;  ?>


<!--    IMAGE URL HARD CODED     -->
<!--
       <img src="http://localhost:8888/wordpress/wp-content/uploads/2018/07/premium-king-room-1900x1060-1345x750.jpg" alt="">

       <img src="http://localhost:8888/wordpress/wp-content/uploads/2018/07/woman-at-canopy-central-cafe-1900x1060-1-1345x750.jpg" alt="">

       <img src="http://localhost:8888/wordpress/wp-content/uploads/2018/07/hotel-exterior-1900x1060-1-1345x750.jpg" alt="">

-->

        <div class="masthead_overlay"></div>
    </div>
    <div class="center carousel-control-container">
        <a href="#" id="prev">
            <span class="icon-arrow-left"></span>
        </a>
        <a href="#" id="next">
            <span class="icon-arrow-right"></span>
        </a>
        <div class="carousel-counter">

        </div>
    </div>



  <?php endwhile; ?>

</header>