BigQueryQueryToTableIT.test_big_query_legacy_sql - fails in post commit tests

Logs: https://builds.apache.org/job/beam_PostCommit_Python35/1123/testReport/junit/apache_beam.io.gcp.big_query_query_to_table_it_test/BigQueryQueryToTableIT/test_big_query_legacy_sql/

Error Message
Expected: (Test pipeline expected terminated in state: DONE and Expected checksum is 158a8ea1c254fcf40d4ed3e7c0242c3ea0a29e72)
but: Expected checksum is 158a8ea1c254fcf40d4ed3e7c0242c3ea0a29e72 Actual checksum is da39a3ee5e6b4b0d3255bfef95601890afd80709