New update
$image = get_sub_field('image');
if( have_rows('slider') ) :
$image = array[…]
if( have_rows('slider') ) :
$image = get_sub_field('image');
$image = false
But before currnet row changed only after the_row(); function.
Fixed my issue by rename custom post type
I had same issue, but with list of field group http://take.ms/kTC0X