No luck so far unfortunately. I emailed the REST to ACF plugin author (who replied very quickly!) and he confirmed there currently isn’t an action to indicate an item was saved. His only suggestion was a filter that runs prior to saving ACF.
add_action('acf/rest_api/post/prepare_item', function($item, $request){
// do something
}, 10, 2);
Not too sure if that would help anyone else – if someone finds a creative solution please let me know!
For the time being, I’m thinking of just setting up a CRON job to email every x amount of minutes/hours.
