Yes. I'm not quite sure what the 1042 tax form is, and I will query that. But the US has an agreement with Portugal.
"For 2020, we will withhold royalty taxes for all writers to send to the US government. For non-US writers (non-resident aliens that are not US taxpayers), the withholding rate is determined based on the country you filed in your W-8 tax form and any tax treaty benefits you have claimed. When filling out your taxpayer information, please include your valid taxpayer identification number (TIN) and, if you reside in one of the countries listed here, select your country of residence under the section “Claim of Treaty Benefits (Part II)”.
In Portugal, I will pay 10% to the United States government.
No other country in the world does this.
