See here, for example: https://wordpress.stackexchange.com/questions/51596/wordpress-does-not-return-404-when-the-url-is-changed
The OP knows that the behavior is a bug, and even links to the Trac bug report he submitted.
What value, then, does such a question provide for the WPSE community? Should such questions be considered off-topic, or should they be re-phrased to solicit work-around solutions in lieu of the bug report being closed/fixed?