Errors in the mobile gaming GameStats pipeline

When running the GameStats pipeline, a bunch of dataflow-related erros seem to be occurring. This is not a 2.5.0 release blocker.

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2018-06-11 14:39:35.725 PDT
Check failed: global_data_producers_.emplace(tag, computation->computation_id()) .second side0
Expand all | Collapse all {
insertId: "5542278371401226255:829484:0:12190"
jsonPayload:

{ line: "environment.cc:60" message: "Check failed: global_data_producers_.emplace(tag, computation->computation_id()) .second side0" thread: "743" }

labels:

{ compute.googleapis.com/resource_id: "5542278371401226255" compute.googleapis.com/resource_name: "beamapp-boyuanz-061121170-06111417-y1cw-harness-sqw8" compute.googleapis.com/resource_type: "instance" dataflow.googleapis.com/job_id: "2018-06-11_14_17_05-8449944902450710343" dataflow.googleapis.com/job_name: "beamapp-boyuanz-0611211703-960649" dataflow.googleapis.com/region: "us-central1" }

logName: "projects/google.com:clouddfe/logs/dataflow.googleapis.com%2Fshuffler"
receiveTimestamp: "2018-06-11T21:40:04.215594890Z"
resource: {
labels:

{ job_id: "2018-06-11_14_17_05-8449944902450710343" job_name: "beamapp-boyuanz-0611211703-960649" project_id: "google.com:clouddfe" region: "us-central1" step_id: "" }

type: "dataflow_step"
}
severity: "CRITICAL"
timestamp: "2018-06-11T21:39:35.725620Z"
}