I got same error.
The reason is that Javascript is loaded before acf_form() generating ACF elements.
Bad case.
<?php
acf_form_head(); // <-- bad!
get_header();
?>
<?php acf_form(...); ?>
Correct.
<?php
get_header();
acf_form_head(); // <--- here!
?>
<?php acf_form(...); ?>
