I had ACF working fine for a time, then I did update some fields of a group, and suddenly those fields stopped saving/updating data.
Thought it was because of other plugins, so i did deactivate all plugins, even reset data for WPML, but nothing changed.
So far, every field I update or add, its value will not be saved at all. this is very frustrating, and I have been testing with every possibility I could think of.
I have tried: Deactivating other plugins, and fall back to parent theme instead of child. Nothing worked.
Tried to follow all instructions of best practices like following page:
WP version 4.3.3
ACF PRO 220.127.116.11 (provided by a theme)
I have figured it out.
the problem is that I did add “add_filter” that changes the “post_name” field in the “posts” table every time the slug needs to be updated, and “acf-fields” in my case requires to be untouched.
hope this solves the problem for someone else.