Hi Eckehard,
i had a similar issue with port collisions on port 8080.
I could prevent the collision by setting the streamsheets-gateway from 8080:8080/tcp to 8082:8080/tcp
So the internal docker-network port is still 8080, but on your local machine the gateway is listen to 8082.
For my simple testing purpose this was the solution.
you can change this port in the docker-compose File
More about the ports from streamsheets and how to change them you can find in this Thread: Port Usage Streamsheets
Cheers