Webhook with JQL and custom issue property not triggering

I’m building a connect app, and want to receive webhooks when certain issues are updated. In my app I’ve added an indexed property, and I can query this successfully using JQL in the UI. The property looks like this:

{
  "my_app": {"linked": 1, "key": 12345}
}

Querying for “linked” issues works fine in the UI, using this query.

issue.property[my_app].linked = 1

But when I add this to a webhook (either created manually or via REST) it doesn’t trigger.

The docs say

any indexed issue property can be queried

Why isn’t my webhook triggering? It works fine if I create one manually without any JQL.

Thanks

OK, slight update. I managed to get the webhook to trigger by changing the filter to:

issue.property[my_app].linked = "1"

Even though linked is registered as a number in the index, and it works fine without quote in the UI.

However, this only works for a webhook registered through either the app descriptor, or created manually. It still doesn’t work for ones created through the API. Ideally I want to create them through the UI so that I can put my own parameters (non-JIRA parameters) in the URL. Is this going to be possible?

Thanks