"submission-created.js" runs but skips call to Airtable...?

You have console.log("Saved") outside base(AT_SUBSCRIPTION_TABLE).create() so it will log that to the console regardless (as I read it.)

Perhaps try logging out base as see that you get.

You also have console.log("Configured"); however you have no check to see that it actually is configured. Does airtable.configure({apiKey: AT_API_KEY}); not return something to tell you operation succeeded or failed (same thinking with base)?