Hi @remseo
I apologize for the delayed response.
I tried what you recommended but did not work. However, I did figure out a way to make it work. I had to first surround everything in the have_rows() and the_row() of the group field.
This is what worked for me:
$group = get_field('group_field');
$heading = $group['heading'];
$text = $group['text'];
// repeater field is called 'links_list'
// repeater sub field called 'link'
if( have_rows('group_field') ) : while( have_rows('group_field') : the_row();
?>
<h3><?php echo $heading; ?></h3>
<?php echo $text; ?>
<?php if( have_rows('links_list') ) : ?>
<ul class="links-list">
<?php while( have_rows('lists_list') ) : the_row(); $link = get_sub_field('link'); ?>
<li><a href="<?php echo $link['url']; ?>" target="<?php echo $link['target']; ?>"><?php echo $link['title']; ?></a></li>
<?php endwhile; ?>
</ul>
<?php endif; ?>
<?php endwhile; endif; ?>
