Docker 500 error: Service endpoint with name already exists

With gitlab 8.11.3 and runners 1.5.2 we are facing the following issue when starting a docker-based build (registry removed / XXXed)

Running with gitlab-ci-multi-runner 1.5.2 (76fdacd)
Using Docker executor with image XXX:build ...
Pulling docker image XXX:build ...
ERROR: Build failed (system failure): API error (500): service endpoint with name runner-5bc3b764-project-112-concurrent-1-predefined already exists

The only thing helping right now is to restart the runner and the gitlab server. Is this a known issue / configuration problem on our side? After retrying several times the build eventually restarts, however, subsequent builds run into the same issue..