do a google search on "coinbase bank of america", you can find a lot about it
There is what turned out.
Bank of America only sends "wire transfer" when you pick 30-dollar fee for the same-day transfer.
The next-day or three-day transfer are sent by ACH. BoA does not show difference in the three transfer option.
My money was sent by BoA ACH to a wire account, and my money stuck between BoA and coinbase's bank.
Had to call many times to sort it out - BoA gave me varies explanation from different divisions and agents - from social media department, wire transfer department, ACH department and finally claim department. Guys, if your fund is stuck, call your money sending bank and ask to speak to their "digital claim" extension. ps, contact BoA support in tweeter, that's most prompt answer.