Upon upgrading from ACF 4.3.9 to ACF Pro 5.1.0, compatibility with the Shopp plugin seems to have broken. I am using a Relationship field to create a many-to-many relationship of posts to Shopp Product objects, and in 4.3.9 everything worked as expected.
Upon updating to Pro 5.1.0, however, I am no longer able to make changes to ACF fields attached to the Shopp Product post type. The existing data is still in place, and queries for the Relationship data still work as expected, but upon trying to save changes to a Shopp Product after updating an ACF field in WP Admin it presents the message “The changes you made will be lost if you navigate away from this page Are you sure you want to leave this page?” Upon choosing ‘Leave this Page’, the changes to the ACF field content is discarded and no update is made to the database.
Are there any tricks I am missing in order to get these two plugins to work together, once again?