started a thread on github (https://github.com/Graylog2/graylog-docker/issues/89), got displaced to the community forum.
Im using the latest docker-compose from here example (https://docs.graylog.org/en/3.1/pages/installation/docker.html) the only thing whats different in my setup is that i map the journal to the host machine instead of using a volume. Stacktraces and More debug information you can find in the github thread wont copy it here (I hate redundancy!).
When its getting stuck it helps to delete the journal, recreate the docker containers then it runs again (for a couple of days/hours), until its getting stuck again.
Switched now to a docker volume (like the example says) and it seems running till now, but i can clearly say its the reason only in a couple of days…