PHP APM errors not showing on Kibana dashboard

Hi,

I'm currently running a PHP project in Kubernetes (php7-fpm, nginx etc..). On this project there is a seemingly successful setup of apm-agent-php in the php-fpm deployment. Kibana shows me APM transactions, BUT the problem is, I get no PHP errors showing on the APM error dashboard.

To make things easier for any friendly soul out there helping me, I put together a simple project (not Kubernetes). But instead - docker-compose with a basic sandboxed Elastic APM + Kibana + a simple PHP project to demonstrate a simpler setup than Kubernetes, with the same problem.

Feel free to clone the project and play around and see what I'm missing in the setup.

Demo project with the problem

Kibana version:
7.13.1

Elasticsearch version:
7.13.1

APM Server version:
7.13.1

APM Agent language and version:
apm-agent-php_1.1_all.deb

Fresh install or upgraded from other version?
Fresh install, see demo project.

Description of the problem including expected versus actual behavior. Please include screenshots (if relevant):
With APM agent in my PHP project, where transactions are shown on the Kibana dashboard, I expect that when an unhandled exception occurs, or HTTP 5xx error code - it should show on the dashboard for APM errors. I have never seen ANY error on the APM error dashboard. So something is off in my setup.

Steps to reproduce:
Clone and run the Demo project, see link above.