Thanks @DavidD66 !
I reached out to Justworks but this is their response: "While we did the filings for both companies as a PEO, you still had two worksite employers in 2020, leading to the excess withholding when your wage base reset. In this case, you would have to file an amendment to your taxes to received the refund. While we are listed as the employer on record, we are not your worksite employer, who would be responsible for the refund".
It seems like I should use schedule 3 of Form 1040, which is the solution for multiple employers in the link you shared. But Turbotax does not detect it as "multiple employers" since I have one unique W2 with Justworks' EIN. Do you know how I can tell Turbotax to consider it as "multiple employers" so that they automatically fill out this form for me?
