AND @junaidbhura above offers a WONDERFUL solution also!
http://www.junaidbhura.com/wordpress-admin-fix-fatal-error-allowed-memory-size-error/
All nested repeater memory hog issues are now a thing of the past!!
This should be in the ACF documentation!
@wootimes solution solved this for us!!
define('WP_POST_REVISIONS', false );
We have a nested repeater with a lot of data records – increasing and maximizing memory was no help to us, nor did switching to a VPS server
THANK YOU!