Web SDK Purchase custom metadata is always null in the event details and related webhook event

Hi.  Whenever I supply custom metadata in my Web SDK purchase call (as described here https://www.revenuecat.com/docs/web/web-billing/custom-metadata), the Event Data for the purchase shows a “metadata” value of null, and the webhook request body for that event then also shows a “metadata” value of null.  I’m using a web billing app.

The exact request I’m making is:
 

const { customerInfo } = await Purchases.getSharedInstance().purchase({
  rcPackage: pkg,
  metadata: {
    org_id: "01970d2a-3f5b-724c-b306-5aca641ffba3",
    event_id: "01972cdb-f765-756b-ae95-203f516ff6e6"
  },
});

I can see the metadata being set correctly in the POST request to https://api.revenuecat.com/rcbilling/v1/checkout/start, it just never seems to actually be stored and associated with the event once the checkout is completed.

I’m using the @revenuecat/purchases-js library on version 1.4.3.  

Is there something I’m doing incorrectly or am I missing something?  Or is there just a bug with processing this metadata on the backend?  Thanks in advance.