I electronically filed an amended 2019 federal return on March 5, 2021 through TurboTax, which printed out an electronic postmark certificate listing a submission and federal acceptance date of March 5, 2021. However, the IRS “where’s my amended return site” still says “Your amended return information is currently unavailable in this application” 12 weeks later. Is it possible it is taking this long for my return to show up in the IRS system as having been received, or should consider it lost and refile it by mail?