Every single tax year the IRS will pull small batches of tax return to test out their systems ahead of the official start date. Those returns, if truly accepted by the IRS, were part of those batches. However, those returns will not be processed until the IRS opens on the date they have specified.
IRS website announcing the start date of January 29, 2024 - https://www.irs.gov/newsroom/2024-tax-filing-season-set-for-january-29-irs-continues-to-make-improve...
