For your first issue, groupings are treated similar to repeater fields but there is a single row of data in that value.
Visually, it appears as a repeater within a repeater.
<?php
// Check for grouping.
if ( have_rows( 'price_information' ) ) :
while ( have_rows( 'price_information' ) ) : the_row();
// Check for repeater.
if ( have_rows( 'event_cost_structure' ) ) :
// Loop through the rows of data.
while ( have_rows( 'event_cost_structure' ) ) : the_row(); ?>
<p><?php the_sub_field( 'option_name' ); ?> : <?php the_sub_field( 'option_price' ); ?></p>
<?php
endwhile;
endif;
endwhile;
else :
// No rows found.
endif; ?>
For the second issue, it seems to format the date correctly on my end…What are your organizations and settings in regards to the display/return format for the Date Picker?
