The plugin doesn’t Clear All fields. After I click on Clear All, all the fields are unchecked but once I ‘Update’ the page, it reverts back to checked fields.

Please assist.

https://www.ads-software.com/plugins/advanced-custom-fields-categories/

I think the update that was just released broke your plugin. When I go to the taxonomies, I no longer see the meta boxes I created and assigned.

Pro 5.2 change log related to taxonomies.
Taxonomy field: Fixed bug where term relationships were not saved when using the update_field() function
Taxonomy field: Added compatibility for upcoming term splitting in WP 4.2

https://www.ads-software.com/plugins/advanced-custom-fields-categories/