Yes, that's all correct; opening a .tax2020 in TurboTax Home Business 2020, & it returns details from my 2019 return (but none of the 2020 information I had entered online.) Thank you for the thoroughness!
Redownloading & renaming was a good suggestion, but unfortunately returns the same results. Notably, as soon as it opens in TurboTax, the file size changes from 5mb to 3mb, which seems to indicate that information is being discarded somehow.
