Docker network remove failed, is that a bug ?

Hello everyone,

Since our last major upgrade (kernel + dockerd) on our Gitlab CI docker runners (running on Ubuntu 20.04 with last docker.io package version 20.10.7-0ubuntu1~20.04.2) we randomly face an error removing docker networks created by our CI...

a "docker network rm" tells us that the network has active endpoints but a docker inspect on the network does not show any...
We do not have any container running (or even stopped) during this manual removal except for the "gitlab/gitlab-runner:latest".

The only solution we found for now to "fix" this state is to restart the docker daemon.

Does anyone has a clue on how we could analyse this problem further ? Any kind of "ghost container" ? Should we fill a bug report ?