Stop in for a cup of coffee

So I’ve gotta go into the state BmV office. Tried to transfer my plates over and the local one is wanting me to pay 2020 excise tax, late fees and registration on the Durango I just bought PLUS all of 2021 stuff because apparently it was never plated last year. Why that is my problem, they can’t say but I’m not paying an extra 700 freaking dollars

If it's new and unsold why would it be plated for the previous year?