When I go to save the product in Magento 2.3 then I get the following notice.
[2019-03-16 14:23:27] main.CRITICAL: Notice: Undefined index: category_id in vendor/magento/module-catalog-url-rewrite/Model/Category/Plugin/Storage.php on line 52
Hello @Anuj Pr Singh
Here I found a link. I think it can help you.
--If my answer is useful, please Accept as Solution & give Kudos