Upsert complains about lack of constrains despite the fact they are present about duckdb HOT 4 CLOSED

import duckdb
conn = duckdb.connect()

conn.sql(
    f"""
        DROP TABLE IF EXISTS meta_test;

        CREATE TABLE meta_test (
            id TEXT NOT NULL UNIQUE,                
            last_ts TIMESTAMPTZ,
            first_ts TIMESTAMPTZ,
            PRIMARY KEY (id),
        );            
    """
)

conn.sql(
    f"""
        INSERT INTO meta_test (id, last_ts, first_ts)
        VALUES ('uuid42', NULL, NULL)
        ON CONFLICT (id)
        DO UPDATE 
        SET last_ts = NULL
        """
)

duckdb.install_extension("postgres")
duckdb.load_extension("postgres")

def postgres_connection(tz="UTC"):
    db_config = settings[env_settings.ts_datastore]
    conn = duckdb.connect(
        f"postgres:user={db_config.user} password={db_config.password} host={db_config.host} dbname={db_config.db_name}"
    )
    conn.sql(f"SET timezone to '{tz}'")
    return conn