Comment 1 for bug 1516144

The real error appears to be

2015-11-13 19:01:10 INFO juju.worker runner.go:275 stopped "unitassigner", err: "4873074d-7936-4e66-89dd-4ffb6e4d7f3b:dummy-source/0" is not a valid unit id

I think this is a difference with how tags and unit ids are converted with jes enabled.