Collabora Nextcloud APP cannot handle reverse apache proxies

Any news?
Was someone already able to reproduce the problem?

Todays (7th februar 2019) new version did not fix the problem

I found the solution. If it is located on the same Server and its running on the same domain but for example with different ports only you need to add your external DNS to the /etc/hosts of your host.
You also need to add it to the /etc/hosts/ of the docker container.
Therefore follow these steps:

Get docker containers ID:
docker ps
docker exec -it IdOfContainer bash
echo domainofyourcloudandoffice >>/etc/hosts

This setup allows you to run it on the same domain without any subdomain and only changing the tcp port for collabora on for example 444