Setting incremental does not take effect

[JinLin6564]

version:
dbt core =1.3.3
dbt hive =1.3.1
python =anaconda3/python3.9

I set config and 'is_ Incremental 'is in SQL but does not take effect. After the second execution, it will be prompted that the same table already exists in hive. I checked the SQL and found that converting to 'create table as' is not an insert syntax

test_1.sql:
{{
config(
materialized='incremental'
)
}}

select * from {{ ref('test') }}

{% if is_incremental() %}

where event_time = (select max(event_time) from {{ this }} )

{% endif %}

error：Hive server: Error while compiling statement: FAILED: SemanticException org.apache.hadoop.hive.ql.parse.SemanticException: Table already exists: testdb.test_1