FBM ship date of 12/1 for orders before Thanksgiving

So for all my FBM orders that came in on Wednesday, 11/26, Amazon shows I need to ship them by Monday, 12/1/25. Since I have 1 day handling and only have Thursday 11/27 listed as holiday why then Amazon is giving me until 12/1 and not Friday, 11/28 which is normal business operating day for both USPS and UPS)? Is it glitch and should i ship out on 11/28 or do I really have until Monday to ship out without affecting my metrics?