I recently added the YesIntent and NoIntent to one of my long-lived skills. While the YesIntent is triggering just fine, the NoIntent seems to be unable to be invoked using the normal utterances associated with it. Instead, those utterances are mapping to other custom intents (none of which contain the utterances in question). It is notable that "no" and "no thanks" both map to incorrect intents, but not to the SAME incorrect intent. This has been tested both by voice via a real device, and by text via the skill console.
SkillId is amzn1.echo-sdk-ams.app.088a5c63-a5ce-4de0-a45a-bed6ec82fb42