Hello mates,
Same error but on “Add to Gallery” button on custom content type. It’s strange but on regular page button working without errors. Reverting to previous version works like a charm.
Enabled js debug showing:
ReferenceError: Can't find variable: post_id
/wp-content/plugins/advanced-custom-fields-pro/assets/js/acf-input.js?ver=5.3.8 line 6147