https://luci-milo-dev.appspot.com/swarming/task/34a85cd4a1701410?server=chromium-swarm-dev.appspot.com
is complete with an internal failure, but the last step is yellow.

Perhaps, if a build is complete, we should mutate the proto we receive from logdog so that we don't render running steps. Running steps must be marked as infra failures.

If the build is green or red, but there are running steps, this is a bug somewhere in LUCI stack. We should receive an alert about it. We don't have a good alerting story for such events, so just logging an error will probably be enough for now.