UNLOAD to parquet does not work for arrays

using

UNLOAD(SELECT * FROM TABLE) TO 's3://...'
    WITH (format = 'PARQUET',compression = 'SNAPPY');

there is a column in table with is an array which comes back withParquet record is malformed: empty fields are illegal, the field should be ommited completely instead. How do I unload parquet if the column has arrays?