@robnero Nope. I tried that too, but I don’t think the $_POST variables have been established before the form submits. So they can’t be passed to acf_form_head before they exist. I may be wrong on why, but it didn’t work in testing.
As an aside, using ‘field_1’, ‘field_2’, etc. Doesn’t work at all. At least not filtering with pre_save_post or update_content_value. I’ve only had success with the nonsense-looking field names I pull off of the source code HTML that looks like ‘field_5419e384411cb’ or something similar.
