<h3>What does it do?</h3>
This plugin does nothing else than to use the internal export function of ACF to filter the data from your main page. After that all fieldgroups of your subpage will be deleted and re-imported. So it’s more of a hack than a real sync.
This has the consequence that the ID integer of your posts shoots pretty in height with frequent use. But that doesn’t really matter I think.

Advanced Custom Fields: Multisite Sync

Sync your Advanced Custom Fields to all of your multisite installations with just one click. Needs ACF Pro 5.0+

PRESSMAN

Hiroshi Sekiguchi

kazunao

This plugin adds 2 functionalities for developers who use ACF. 
1. Add a display of field details in ACF form. 
2. Add extra columns in ACF field group list.
For details, see this plugin’s setting page.

Advanced Custom Fields: Multisite Sync vs Developer Tools For ACF