Are you sure it wasn't your Taxes Due that dropped? Did you enter a 1099-G for unemployment? The update takes into account that the first $10,200 of that isn't taxed. Are you using TT online, or TT desktop?
TT Desktop for Windows
No unemployment which I know is the newest change. Fully employed for all of 2020. My federal refund dropped more than $3,000.
Taxes due to 3 different states all increased.
Yes. Every single update that is available has been installed. The most recent is the one that made the erroneous calculations.
I think you need to call TT Support: