test_multimap_multiside_input failing on Spark Python

beam_PostCommit_Python_VR_Spark is red.

18:32:46 ERROR: test_multimap_multiside_input (_main_.SparkRunnerTest)
18:32:46 ----------------------------------------------------------------------
18:32:46 Traceback (most recent call last):
18:32:46 File "apache_beam/runners/portability/fn_api_runner/fn_runner_test.py", line 265, in test_multimap_multiside_input
18:32:46 equal_to([('a', [1, 3], [1, 2, 3]), ('b', [2], [1, 2, 3])]))
18:32:46 File "apache_beam/pipeline.py", line 529, in _exit_
18:32:46 self.run().wait_until_finish()
18:32:46 File "apache_beam/runners/portability/portable_runner.py", line 571, in wait_until_finish
18:32:46 (self._job_id, self._state, self._last_error_message()))
18:32:46 RuntimeError: Pipeline test_multimap_multiside_input_1588026700.62_3808162b-fc6a-4eb0-be3a-3efd819560f7 failed in state FAILED: java.lang.IllegalArgumentException: Multiple entries with same key: ref_PCollection_PCollection_21=(Broadcast(37),WindowedValue$FullWindowedValueCoder(KvCoder(ByteArrayCoder,VarLongCoder),GlobalWindow$Coder)) and ref_PCollection_PCollection_21=(Broadcast(36),WindowedValue$FullWindowedValueCoder(KvCoder(ByteArrayCoder,VarLongCoder),GlobalWindow$Coder))