When connecting to Snowflake, Tableau returns a different timestamp than what is displayed in Snowflake. This issue can arise when working with TIMESTAMP_TZ and TIMESTAMP_LTZ field types, or when returning current_timestamp from the database, while the end-user's machine is set to a different time zone than that specified by the TIMEZONE parameter for their account/session or where the Snowflake database is located in a different time zone.
Because Tableau will query the database using timestamps in the local machine timezone, if the timezone in Snowflake is different, the data returned may be incorrect, or no data is returned at all.
It should also be noted that, when connecting to Snowflake located in a different time zone, current_timestamp and now() return different values. Namely, now() returns the date in the data source time zone while current_timestamp returns the date in the local machine time zone.