Why Turbo Tax ask me to activate after I retore it from an activated turbo tax backup to the same computer

I had  activated Turbo Tax and done my tax, then I back up turbo tax with the whole windows 10 system to my computer. Then I uninstall the turbo tax.  Today, I restore the windows 10 system from the backup which included a activated turbo tax to the same computer.  When restore completed,  I click on the Turbo Tex icon and it first run update then ask me to activate it.   I don't understand why it  asks me to activate it while I restore it to the same computer.   So, I think Turbo Tax software has a bug.  It shouldn't ask me to activate it again if I restore it to the same computer.