@kaust it appears that the way acf/save_post works, or more specifically, the ACF action function works, has been altered. The hook now passes the values to be saved https://www.advancedcustomfields.com/resources/acf-save_post/ and works off of the passed array rather than the $_POST array. What this means is that the alterations that your making to this array are done after ACF had retrieved the values.
What this means is that you’ll need to run your function ACF gets the values from $_POST. I’m not really sure what the best hook for this would be, but I also need to investigate this because I have a plugin that relies on something similar to what you’re doing. I’m thinking that acf/init might be the way to go. I’ll let you know if I find anything else out.
@aydcery you are running into this issue because you are not passing the $_POST[‘acf’] array when calling.
