I already have installed matrix via matrix-docker-ansible-deploy. Now I want to setup nextcloud on the same server via mash-playbook.
As traefik is already running from the matrix-docker-ansible-deploy, in my vars file I have:

mash_playbook_reverse_proxy_type: other-traefik-container
mash_playbook_reverse_proxyable_services_additional_network: traefik

So I can install nextcloud on the same machine as matrix. Unfortunately in Nextcloud when I go to overview, I get this security & setup warning:

The configuration of the reverse proxy header is incorrect. This is a security problem and may allow an attacker to spoof your IP address so that it is visible to Nextcloud. You can find more information in the documentation.

I get rid of the message, when I add the ip raange of traefik as trusted_proxies in config.php:

'trusted_proxies' =>
array (
0 => '172.23.0.0/16',
),

I would have exepcted, this change is reflected by running
just run-tags adjust-nextcloud-config
But this does not seem to happen.
Maybe, this could be added somehow in the playbook, by doing something like
occ config:system:set trusted_proxies --value='{"0":"172.23.0.0/16", "1":"192.168.0.0/24"}'