Distributed media library items lose their ACF fields

[tim-plimsoll]

Describe the bug

When I pull a post from a parent site, the featured image does come over, along with any attached media (if the option is turned on), but any ACF fields associated with those media library items do not come over. This appears to be the same for both featured images and attached media items.

Steps to Reproduce

• Install ACF and Distributor on two Wordpress sites, Site A and Site B.
• Configure Site B to be able to pull posts from Site A
• Create an ACF field group for Attachments on Site A, with a Text field named Test ACF Image Meta.
• Export this ACF field group from Site A and import it to Site B.
• Create a Test Post A on Site A with a featured image.
• Go to the media library on Site A and edit the featured image you assigned to the post, and set the Test ACF Image Meta value to "Lorem Ipsum"
• Pull Test Post A from Site A to Site B, which should bring the featured image along.
• Find the featured image in the media library on Site B.
• The Test ACF Image Meta field will be blank.