Add my husband = excise tax?

Hello.

Last year my then boyfriend and I refinanced our house and I added him to the title doing a quick claim deed. I purchased the home three years prior and made payments to the mortgage company with no issues. We pay the mortgage from the same account (my husband is a signer now). Today I received a notice that I owe excise tax for half of the payoff amount when I refinanced.

This doesn't make any sense since the property was not sold. I live in Washington state. Should I pay the tax or do I have a valid argument to contest this?

Thank you.