Thanks for sharing that. So that item lives in sandbox, so to be clear you would only get webhooks in sandbox for changing it, not in production.
Your sandbox app id as far as I can see is sandbox-sq0idb-5P7DNs8QyQLf0Dh4HVmOrg, which has 159 catalog.version.updated webhooks that have been sent in the last 3 days. With that said, they all look like retries, so it appears you’re not actually receiving or responding to us, so they’re probably not being seen by you. They’re being sent to an ngrok server you provided, so make sure it’s actually running if you’re trying to test this.
Let me know if I’m misunderstanding something here though.