Thanks! I actually did sorta resolve it. I was trying to use a page template specifically for this front end form. Literally the only version in which the form works is when I place the acf_form_head function above my template name code. Not above doctype in my header, not via an ‘init’ hook, this was the only way it worked for me.
<?php acf_form_head();?>
<?php
//Template Name: New Project
?>
I’m having the same problem. The front end form works perfectly fine, but no matter what I do it creates two posts. I have no other plugins installed and my theme is just an Underscores.me theme that I’ve added very basic functionality too.