We had issues replicating to Snowflake connector and both Attunity Support community and Snowflake Support has advised us to raise this feature request to enable Attunity Snowflake connector to add option OVERWRITE=True to avoid Attunity errors when running COPY INTO commands inside snowflake from Attunity.
For reference, below are the support case we have with Attunity & Snowflake..,
Attunity Support Case# 02065074
Snowflake Support Case# 00153712