Trouble getting push notification actions working

I have a Node-Red action running that creates a Notification based of a template like so:

{
   "data": {
        "title": "Tuin beregening",
        "message": "{{^payload.sprinkle}}Wordt vandaag niet gedaan omdat {{payload.whyNo}}{{/payload.sprinkle}}{{#payload.sprinkle}}Gaat over 15 minuten beginnen{{/payload.sprinkle}}",
        "data": {
            "tag": "notification-about-sprinklers",
            "actions": [
                {{#payload.sprinkle}}
                {
                    "action": "sprinklers_action_cancel",
                    "title": "Annuleren"
                }
                {{/payload.sprinkle}}
            ]
        }
   }
}

When triggering this manually, I receive the notification on my phone just fine.

Following some of the guidance of the internet I have an automation in home-assistant like so:

- id: '1589916447959'
  alias: Testing notification cancelled
  description: ''
  trigger:
  - event_data:
      action: sprinklers_action_cancel
    event_type: html5_notification.clicked
    platform: event
  condition: []
  action:
  - data:
      message: ok, dan niet.
    service: notify.mobile_app_samsung_s10

When triggering this manually, I receive the notification on my phone just fine aswell.

En yet, when I press the button on the notification, I get nothing.

I am running home assistant in a docker container: homeassistant/home-assistant:stable
And on another server I have a letsencrypt docker image as reverse proxy:

letsencrypt:
        container_name: letsencrypt
        image: linuxserver/letsencrypt
        restart: unless-stopped
        ports:
            - 443:443
        environment:
            - PUID=1000
            - PGID=1000
            - TZ=Europe/Amsterdam
            - URL=[URL]
            - SUBDOMAINS=wildcard,
            - VALIDATION=duckdns
            - DUCKDNSTOKEN=[TOKEN]
        volumes:
            - nginx-data:/config
        cap_add:
            - NET_ADMIN

Just to be sure I added the following Nginx config:

location /api/notify.html5/callback {
    	if ($http_authorization = "") { return 403; }
    	allow all;
    	proxy_pass http://10.0.0.214:8123;
    	proxy_set_header Host $host;
		proxy_set_header Authorization $http_authorization;
    	proxy_redirect http:// https://;
		proxy_pass_header Authorization;
	}

Manually firing an event from
Developer Tools > Events > Event Type: html5_notification.clicked
Without any event data triggers the automation just fine, which I find strange as I expected that the automation would filter on the sprinklers_action_cancel. But at least it’s something and the automation appears to be working.

Does anyone have any ideas? Thanks!