I hvae no idea how to answer this question:
But you could try to turn off container logs and see if it helps.
docker run -it --log-driver none <image>...
or in compose:
services:
myservice:
..
logging:
driver: none
...
Be sure to never edit the container in the Syno-UI again, as the ui removes settings it doesn’t support.
Aren’t they funny. They altered the sources to make it work with libraries (where they of course altered the sources as well) and added additional features to it… and broke the swarm-mode since it was available in docker-ce 17.05. I doubt that any of their modifications went upstream.
If what they claim is true, the binaries of docker’s official binary releases should be a drop-in replacment for the docker binaries from the Synology docker distribution … well, they aren’t