See here for ACF image docs.
https://www.advancedcustomfields.com/resources/image/
If image field is set to return as an array then you need store the image subfield into a variable and use the variable to output the array keys.
So in your case, it would be like this…
<?php while( have_rows('logo_list') ) : the_row();?>
<?php $image = get_sub_field('image'); ?>
<li><img src="<?=$image['url']?>" alt="<?=$image['alt']?>" /></li>
<?php endwhile;?>
Use the code below inside your loop to dump your $image variable data so you can see all the image sizes and other image data.
echo '<pre>' . print_r($image, true) . '</pre>';
Very strange what is happening here.
Before your loop try adding this to see all the data in the field.
<?php global $post; ?>
<?php $field = get_field('logo_list', $post->ID); ?>
<?php echo '<pre>' . print_r($field, true) . '</pre>'; ?>
Post the output when you’ve done this.