I see the below error in my Apache error log when performing the action.
[proxy_fcgi:error [pid 3963038:tid 3963237 [client 193.91.108.206:0 AH01071: Got error ‘PHP message: PHP Warning: array_flip(): Can only flip string and integer values, entry skipped in /home/HIDDEN_DOMAIN…ning: array_flip(): Can only flip string and integer values, entry skipped in /home/HIDDEN_DOMAIN/dxtzcunmpa/public_html/wp-content/plugins/woocommerce/includes/rest-api/Controllers/Version3/class-wc-rest-posts-controller.php on line 512’
I can provide a staging access (with no data at all) where you can test the issue. Is it ok if I share it here? or elsewhere?
Issue was due to third party customization, no worries.