dateadd is not working properly

dateadd occasionally fails

The screenshot 1 failed but screenshot 2 succeed for the incremental update. is already a timestamp without timezone. It only work when I cast it into text. If I keep it as timestamp, it says

function date_add(text, bigint, timestamp without time zone) does not exist

It is really weird to me, how come the can determine whether the macro (screenshot 3) work or not? The screenshot 3&4 are the utils function I wrote for my project. In addition, this macro actually works in other models in my project where ::timestamp is completely ok. I got really confused on why it sometimes works and sometimes does not.

The screenshot 1 and 2 are almost exactly same expect in where clause > …
vs > …

{{ config(
) }}

{{ simple_cte([
    ('amazonads_dsp_campaigns', 'source_ads__amazon_dsp_report_campaign_performance'),
]) }},

amazonads_dsp_matrics as (

        'DSP' as channel,
        null::bigint as profile_id,
        cam.advertiser_country as country_code, as "date",
        cam.order_id::text as campaign_id,
        "order" as campaign_name,
        '' as ad_group_id,
        '' as ad_group_name,
        sum(cam.click_throughs) as clicks,
        sum(cam.total_cost) as cost,
        sum(cam.impressions) as impressions,
        sum(cam.total_sales_usd) as sales14d,
        sum(cam.total_purchases_clicks) as conversions14d
        amazonads_dsp_campaigns cam
    {% if is_incremental() %}
    where > {{ get_inc_key_timestamp_with_lookback(this, 'date', '', 48) }}
    {% endif %}
    {{ dbt_utils.group_by(8) }}

select * from amazonads_dsp_matrics