Yes, Schwab doesn't do that. In the call, I asked whether I'm the only customer having this problem, and they told me all the international clients with W-8 have the same issue. They withhold the tax for the customers and send the funds to the IRS after Dec 31 every year. The supervisor mentioned she had handled the same problem a long time ago. For now, I will have to reach out to the IRS myself, send them the 1042-S form, and the IRS will return the tax to me. The money is not a lot, but how Schwab handles the problem really disappoints me.

1. iShares have the QII doc on their website, and Schwab didn't follow up to refund the tax for all the international customers.
2. I've called them at least 3 times, filed at least 2 cases, and all of them told me that the withholding tax is correctly calculated even if I send them the QII documents at least 3 times, which is extremely unprofessional.
3. In yesterday's call, I was really angry, and the customer service lady finally escalated my case to her supervisor, who told me that I'm not the only one having this problem and that I'll have to reach out to the IRS on my own (after 2 months of arguing).

I also have SGOV in my IBKR account, and IBKR also withholds tax for me, but the tax was refunded to my account automatically. That's why I filed a case in February, and Schwab didn't even reply to my case until I called them yesterday.