Python Flink ValidatesRunner test_flattened_side_input fails

ERROR: test_flattened_side_input (_main_.FlinkRunnerTest)
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Traceback (most recent call last)
File "apache_beam/runners/portability/fn_api_runner_test.py", line 205, in test_flattened_side_input
label='CheckFlattenOfSideInput')
File "apache_beam/pipeline.py", line 425, in _exit_
self.run().wait_until_finish()
File "apache_beam/runners/portability/portable_runner.py", line 349, in wait_until_finish
self._job_id, self._state, self._last_error_message()))
RuntimeError: Pipeline test_flattened_side_input_1547859357.36_07dcde9b-acfc-4e8d-b930-582f7637a07e failed in state FAILED: java.lang.IllegalArgumentException: PCollectionNodes [PCollectionNode
{id=ref_PCollection_PCollection_12, PCollection=unique_name: "17side3/Map(decode).None" coder_id: "ref_Coder_BytesCoder_1" is_bounded: BOUNDED windowing_strategy_id: "ref_Windowing_Windowing_1" }

] were consumed but never produced