The parameter ui_tls_enabled true needs a tls-secret to be mounted in the ui-deployment. The secret expects a tls.crt and a tls.key (see line 121 and 123 in deployment-ui.yml.j2). 
But unfortunately the secret is not mounted correctly, as seen in line 164 of the above jinja template. 
mountPath: /var/run/secrets/{{ ui_tls_secret_name }}/tls.crt
The /tls.crt has to be deleted, I assume.