Bug: Magento 2 does not require an administrator to enter the URL Key, tries to autogenerate it on a product saving, but do it wrongly and fails with the message: «URL key for specified store already exists»

[dmitrii_fediuk]

A similar issue: A failure while creating a configurable product: «URL key for specified store already exists»

Issue: Bug: Magento 2 does not require an administrator to enter the URL Key, tries to autogenerate it on a product saving, but do it wrongly and fails with the message: «URL key for specified store already exists»