I believe I’m experiencing a similar problem. Most of the images on our site broke after we upgraded to 5.7.11 because of this loop:
while(have_rows('gallery')) : the_row();
$image = get_sub_field('image');
...
Whereas before $image contained the URL of our images, now $image is always just the letter ‘i’
We’ve downgraded to an earlier version and hope that this is something that will get fixed with a point release…
