What version of Materialize are you using?

v0.98.6

What is the issue?

When no FORMAT is specified in a COPY TO command with an AWS CONNECTION, Materialize falls back to the default used for the vanilla variation of the command (TEXT), which isn't supported for bulk exports:

materialize=> COPY mv TO 's3://mz-to-snow/parquet/'
WITH (
    AWS CONNECTION = aws_role_assumption
  );
ERROR:  FORMAT TEXT not yet supported

We should either make FORMAT required when using this variation of the command, or default to one of the valid options.