I looked back and saw that I forgot something important. My code above will create and infinite loop. Someday I should right a book on how to do it 😛
if (have_rows('repeater_field')) {
while (have_rows('repeater_field')) {
the_row();
if (have_rows('flex_content_field')) {
while (have_rows('flex_content_field')) {
the_row(); // forgot this line
$layout = get_row_layout();
// and the rest of your flex field output
} // end second while have rows
} // end second if have rows
} // end first while have rows
} // end first if have rows
