Thanks so much @hube2 that did the trick.
Here’s what the final code ended up looking like:
<?php if (have_rows('folio_items')) {
while( have_rows('folio_items')) {
the_row();
if (get_sub_field('toggle_display')) { ?>
<!-- FOLIO ITEM FLEXIBLE CONTENT -->
<div class="col-md-3 col-sm-4 col-xs-6">
<a class="overlay" data-toggle="modal" data-target="#<?php the_sub_field('project_id'); ?>"><i class="fa fa-search-plus"></i><h3><?php the_sub_field('project_title'); ?></h3></a>
<img class="img-responsive" src="<?php the_sub_field('project_thumbnail'); ?>" alt="<?php the_sub_field('project_title'); ?> Thumbnail">
</div>
<div class="modal fade" id="<?php the_sub_field('project_id'); ?>" tabindex="-1" role="dialog">
<div class="modal-dialog modal-lg">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h4 class="modal-title"><?php the_sub_field('project_title'); ?></h4>
</div>
<div class="modal-body">
<div class="row">
<div class="col-md-9 col-sm-8">
<?php the_sub_field('project_content'); ?>
</div>
<div class="col-md-3 col-sm-4">
<h5>Client</h5>
<p><?php the_sub_field('client_name'); ?></p>
<hr>
<h5>Details</h5>
<?php the_sub_field('project_details'); ?>
</div>
</div>
</div>
<div class="modal-footer">
<a href="#" data-dismiss="modal">Close Window <i class="fa fa-times"></i></a>
</div>
</div><!-- /.modal-content -->
</div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<?php } ?>
<?php } ?>
<?php } ?>
