I’ve attached gif outlining the problem visually. It is an odd issue that happens to one of the sites in the multisite.
To replicate:
1. Add any image to the gallery (single / multiselect).
2. Click save (success message)
3. See that all images disappear
What I’ve tried
1. Compared / Matched the ACF fields to another subsite (which works)
2. Upgrade all plugins and wordpress core
3. Disabled all none essential plugins
Problem still persists. Has this happened to anyone else?