Why does TT's version of form 2210 calc a penalty when my manual method of filling out 2210 does not calc a penalty? I see this same problem existed in 2020! Fixed?

If you get better results filling the forms manually, you'll have to file on paper via US Mail.

The IRS has not yet issued Form 2210 for 2021. The form is currently not expected to be available in TurboTax until March 17, 2022. The Form 2210 that you are seeing in TurboTax now is incomplete and has not been updated for 2021. Try again after TurboTax designates the form as being available.

IRS forms availability table for TurboTax individual (personal) tax products

You might be figuring it out wrong doing it manually.   When you get the final 2210 from Turbo Tax compare it to yours.   Where's the differences?